I have definitely realized over the last couple years that if I am interested in a certain motherboard, I first download the manual for that motherboard and research all of this stuff as there are surprises out there. I have seen in addition to SATA ports being disabled with certain NMVE scenarios, I have also seen Thunderbolt ports disabled in this fashion as well from what I have read in the mobo manuals. Read before you buy is my new mantra!
that's the way to go for since this opportunity exist! (even before manufactures did it themselves, there's still many manual hosting sites online!^^ - hell, ppl even manually scanned pages back in the day to make them public xD)
@@viperrcr I'm guessing with the high-end boards (or 2025), you can reclaim the dormant 8 lanes from the X16 slot, but it defeats the purpose since most at that price point would spend more on a GPU ??? At least AMD 8700G APU would allow for a free X16 slot for storage provided no GPU installed.
Not sure about all AM5. But the 7800X3D has 28 lanes total. 4 for chipset and 24 usable. So you can have your whole x16 GPU + x4 M.2 G5 and 4 to spare. And the B650E and X670E chipsets have 36 and 44 usable respectably with 24 been Gen5. The original X670 only had 8. So the X670E that come with PCIe G5 and an M.2 G5 they don't have to split it. They do everything else with the other lanes. Probably why so many boards share M.2 with PCIe slots or Sata ports. Unable to used them all simultaneously. To prevent stealing from the GPU or M.2_1. This seems to be an intel specific thing. The LGA 1700 is limited to 20 lanes, and only 16 been gen 5, the other 4 are Gen 4. LGA 1851 will address this by having 20 Gen 5, x16 for PCIe slot and x4 for storage. And an aditional 4 Gen 4 lanes. So depending on the manufacture and how they allocate them. There should be boards that can do both at full speed. Asumming the rest of the PCIe slots and M.2 are split between the remaining 4 G4 and the chipset.
@@Omizuke The point is, they took away the dedicated bus lanes for other devices, such as PS/2, USB, Parallel ports, serial ports ,PCI, AGP, IDE, SATA, Onboard Audio, NIC, etc and placed it all on PCIE without expanding the amount of PCIE lanes.
This is why I miss the old enthusiast line of core i7s that used the LGA 2011 socket. Besides having quad channel RAM, those had enough lanes where you could even run a full dual GPU setup using 16x16 lanes, and still had a few to spare. They need to update the enthusiast line and bring it up to full pcie gen 5 spec.
Having been an "Electronics Junkie" for decades, I learned what you cover here the hard way, long ago. (When the going gets weird, the weird turn pro. -Revenge of the Nerds;-) So, I moved up to Threadripper!@@TheProvokedPrawn
Too complicated for gamers. The nvme drives can also run really hot. I only use a single drive in the slot I can easily cool with a extra fan. Usually the bottom slot. There’s not that much real world speed difference for an average user between a nvme and a sata ssd. It’s not like going from a mechanical was.
It's daibolical researching this. You literally have to read the manual of every motherboard you're looking to buy. This was supposed to be easier with AM5, but the B650 and X670 chipsets then got inexplicably split into B650/B650E and X670/X670E which made the whole situation as clear as mud. Why AMD didn't just say, "B650 is PCIe Gen 4 for everything and X670 is PCIe Gen 5 for main M.2 and first PCIe expansion slot" is a mystery to everyone.
You can get kernel instruction pipe issues, cpu affinity, nvme driver code, to the fact that some boards may have one slot(main) apart from 3 slots on a switch before it hits the root complex, or any combo thereof. I'm not saying anything throttles down, but even the test software is baked, based upon the fact that threads rent time on a single instruction queue, assigning workload to any given logical processor. The OS could prioritize your system drive, and assigning workload at that level, start grinding. OSes do go thru kernel and driver updates for said reasons. This is not the first time the hardware has outstripped the OS. I would use one 5.0 drive and leave it at that. Buy the biggest one, not 4 of them because 6 is already specced out. When you're brand new, you're retro.
Just be sure to check the GPU with something running. the GPU goes into standby and changes the speed of the PCIe when nothing big is rendering, so that information is not correct if you don't have something actually being processed by the GPU. That's why on GPUz there's a rendering test near that info.
I skipped M2_1 slot for my z790 dark hero because using gen4 still cut my gpu to x8, so I put my system on M2_2 instead, which still connected to the cpu.😅
@@Matlockization untrue. Most cards cannot fully saturate 16 lanes of pcie 4/5 yet. However GN and HU have shown the 8 lane budget cards take a performance hit on pcie3 motherboards
Well, all z690/790 boards that have PCIE gen 5 m.2 slot(s) will always halve the first X16 PCIE slot down to X8, regardless of the brand of the board you use.
Even if you install an PCIe 4.0 SSD into the Gen 5 Slot? As far as I know, they share the same physical connection I think? EDIT: NVM, I should've finished the video before commeting. I only was halfway through it when asking
Glad you doing this video. I upgraded my PC from an i7 4790k to a i9 13900k with an Asus Z790 Hero which I thought I could use at full speed with x5 NVME drives. Not so. I've installed 4 now, plan to add a 5th one soon. I think AMD Threadripper has much more M.2/NVME drives slots that any other chipset.
Great video! Thank god these are some very specific high-tier problems, affecting only a tiny minority of users. For example, If you can afford a 700 dollar motherboard, then spend money on bigger SSDs instead of several smaller ones. If you can't afford those SSDs, spend less money on the motherboard. You can get an excellent DDR5 motherboard for $200-300. Usually, no point in having four or five 1Tb NVMe SSDs in your motherboard. Just buy two 2-4Tb SSDs and be done with it. Also, almost nobody needs these speeds on their SSDs. You don't benefit from it, unless you transfer massive amounts of data on your system regularly, or you do some extreme simulation with huge data amounts (although the work pipeline bottleneck in simulation usually is not the data transfer rate of an SSD, but the CPU, unless you're using a $20k super home computer with 2 physical CPUs with 128 cores both, or something like that). Only 0.1% of PC users will actually benefit from the PCIe 5.0x4 (4 lanes, 4GB/lane) 16 GB/s data transfer speed compared to the 8 GB/s speed on PCIe 4.0x4 (4 lanes, 2GB/lane), so the 99.99% of us peasants are doing just great with the PCIe 4.0 speeds. Gaming doesn't benefit from the extra speed at all, and even heavy video editing or most productivity workloads doesn't benefit from it. The work pipeline bottleneck is pretty much always elsewhere.
"Almost nobody needs these speeds on their SSDs" lol. ALL PC gamers need those speeds. Games are bigger and more texture rich than ever to the point that SATA SSDs and slower NVMe drives are falling behind. NVMe drives show very noticeable gains in loading times with newer games even without specific optimization. Any games with Direct Storage show massive gains. Some games like Ratchet and Clank have fundamental changes in gameplay based on your drive speed.
very helpful information. I did a lot of research on my board and drives before pulling the trigger to purchase. I'll make sure to reference this video when I need to assist others
The motherboard manuals show how the lanes are divided. From what ive seen on many AM5 boards, the top nvme slot steals lanes (which goes against the meta we've been accustomed to for the past few years)
I believe the Asrock X670-E Taichi runs the PCIe gen 5 NVME through the chipset, allowing the PCIe x16 for the GPU to run uninterrupted to the CPU, unless of course you use the second PCIe slot.
I have an ASRock X670E Pro RS and can fill all the m.2 slots and still get 16x Gen 4 for the GPU, depends on the CPU and motherboard type, if the motherboard has it's own controller chip for M.2 drives I think it frees up some lanes from the CPU.
controller chips still need pci-e lanes to connect with the cpu. what the issue is, you can have all your nvme's connected and r/w at max speeds, the chipset bandwidth is limited. so tranferring data from all of them at the same time doesnot addup because the chipset has to share the bandwidth with every device it has. it's a common misconception, the fact that the drives are working at full speed, doesnot mean that the data are going to the cpu at that rate.
You definately gave me something to think about. I've got an open NVME spot and was gonna buy another drive while I had some extra money. Now I gotta see what impact that will have on my board. Asus PRIME Z790-P WIFI ATX LGA1700. Wasn't going to choose it, but it was part of a bundel at Micro Center, and a great deal price.
This has been a problem for years. I Used an MSI x370 gaming carbon pro and the second nvme slot disabled one of the SAT slots if a NVME was fitted. The PCIE slot 4 was only 4 lanes but it ran my EX570 woth no problems and I got a 4 nvme addon card which I used in the PCiE 16 lanes. I wanted to go to a MATX and Ryzen 5700G thinking I could use the 4 way card for 4 NVME drives by making the PCIE slot 1 into a 4x4x4x4. No the Ryzen 5700G only supports 8x4x4 so thats t nvme drives. The Board us an Asrock b550 pro 4. I was aware the second nvme position only operated at PCIE2 if used as nvme and also disabled a SATA position. I knew the Ryzen 5700G was only PCIE 3 but that did not bother me. I was counting on using the 4 port nvme card in the PCIE 16 lane running 4x4x4x4. But as noted above the ryxen 5700g will not do that. I think its rather stupid of AMD not to think a user of integrated graphics might want to use the graphics slot for something else. I am now tied to noo graphic card in this system as I am fitting a 2 port nvme adapter with a chip card into the second long pcie slot that runs 4 lanes. The whole thing of what happens is not documented well by anyone.
I have the same board and only use the top drive and get x16 on my 4090. So it might not be what you think? Maybe if you fill all with gen 4s or just top with gen 5 it locks it to 8x.
chips only have a limited number of specific generation PCIe lanes, you can also have PCIe switches on a board that will split up a higher gen lane to multiple lower gen lanes, but this isn't always the case. for the i9-13900k that has 20 PCIe lanes maximum and support gen 4 and gen 5 in the following configuration 'Up to 1x16+4, 2x8+4'
So, uh, question: Have you tried checking the lane usage while actually USING the graphics card for something? To see if it is prioritizing bandwidth to the gpu when it is going full tilt, but leaving it in a lower bandwidth mode when it isn't using that bandwidth? Obviously, test while gen5 slot is idle, but might be something worth checking. It's also a good thing to remember that for most consumer uses, an NVME doesn't provide much, if any, noticeable benefit over a SATA SSD. So you can usually just whack a Sata ssd in instead of using that gen 5 slot. Also, yes, always a good idea to check the specs of parts BEFORE purchasing them by looking at the more detailed data available on manufacturer's site, instead of just marketing slides. It's helpful for pretty much EVERY part.
An LGA1700 CPU offers 20 CPU PCIe lanes. This includes 16 PCIe 5.0 lanes and 4 PCIe 4.0 lanes. If the motherboard designer chooses to employ PCIe 5.0 for the primary ("top slot") SSD, those lanes must be borrowed from the lanes allocated to the GPU, so the GPU gets 8 lanes, the SSD gets 4 lanes, and 4 lanes (of the 16 allocated to the GPU) will go unused. Even when a PCIe 4.0 SSD is installed in the top slot, the board's architecture is still employing 4 lanes from the GPU, so the GPU will get only 8 lanes. If you want your GPU to have 16 PCIe 5.0 lanes on a board like this, you need to leave the top slot unpopulated. Intel's upcoming 15th gen Arrow Lake (LGA1851) will remedy this by increasing the PCIe 5.0 lanes from 16 to 20 (in addition to the 4 lanes of PCIe 4.0).
The sticker on NVME SSDs actually serves a purpose by transferring heat from the controller to the NAND chips, which need the temperature to work well.
With the mpg z790 edge TI Max wifi, it explicitly states in the instructions that if m.2 slot 1 is used, it will knock your x16 gpu slot to x8. This is because the #1 m.2 shares the same bus as the x16 slot, which is shared directly with the CPU itself. If you want to make full use of your gpu, leave m.2 slot 1 empty. Also, if you use the m.2 slot 3, your sata data 1 & 2 is useless. Same principle with the exception that m.2 slots 2-5 are managed through the z790 chipset. That chipset mangages other secondary interfaces as well. These technical phenomenons are common place and are mentioned in CompTIA a+
I really like my MSI board for NVMEs it's a B550 tomahawk. It actually lets you decide how you want the lanes split... kind of. 8+8, or 8+4+4, 4+4+4+4 and then everything is full. Mine is currently 8+8 cause I'm just using 1 NVME so everything is nice and quick. I will be upgrading eventually so I'll dumb it down to 8+4+4 but my GPU will still be full speed while the NVMEs get to share. That being said it doesn't have a thermal pad on the board side like yours does! It has the heatsinks for the top if the NVME doesn't have its own (mine does) but nothing for underneath.
I`m not suprised by this, i did notice however that even on MSI`s webpage for this Z790 motherboards specs and even in it`s manual it nowhere mentions the sharing of pcie lanes, wonder if you have bandwith bifurication option in the bios on this board. these kind of issue`s is the reason for me why i went with a AMD 7950X and a X670e board. 1. amd gets you 28 pcie lanes instead of intel with 20 lanes 2. X670e gets you a lot of additional pcie 4.0 lanes. i can easily install 5 nvme`s of which 1 is pcie 5.0 and still have pciex16_1 slot run x16.
I JUST got a couple new drives to fill the last couple spots on my board. Haven't noticed any problems, but also didn't know this was a possibility so haven't checked...
It's still oversubscribed, five SSD need 20 lanes but they have to share four PCIe 4.0 lanes and eight DMI 16GT/s lanes at the CPU. If the drives are used simultaneously it might be better to split the x16 slot for a Gen 5 SSD. This is one area where AMD is more flexible, you can have up to 5x Gen5 SSD, and only 2x on Intel
Before buying any motherboard, download and thoroughly read the motherboard instructions, as most do describe the limitations and trade-off in propagating the different types of data storage/transfer ports, it saves on time, money and broken expectations; laziness and or rushing are often the cause of so much heartbreak!
If you’re running an 12th, 13th or 14th gen Intel cpu, and a z790 motherboard, you get 20 lanes on the cpu, so 16 for the graphic card and 4 for the M.2. That then leaves you 20 lanes on the chipset, which can handle upto 5 gen 4 M.2. Only becomes an issue, if you start using any of the other pcie slots
Yes this is all True. I've been building my own Gaming configurations for 40 years. I currently use the Asus ROG Strix B550 XE Gaming Motherboard & 2 TB NVME M.2 SSD Ryzen 7 5800X CPU. Yes installing another M.2 in the lower slot will split the Lane Traffic to half. Instead of 16X they will both be 8X.
How do you research this? Will it state somewhere in the specs? I understand how to test once you have the parts, but id obviously like to know before purchasing
@@TheProvokedPrawn I've looked into this a bit (actually how I found your original video) and as far as I can tell this is a problem across all Intel motherboards, at the very least the z790 ones
All you need to know, is how PCIe lanes are distributed. You can divide PCIe lanes (usually done to CPU lanes), or create new ones ( chipset ), but if there’s not enough, you can disable some of them. The problem is simple, cost. There was also no mention of max speed of chipset to CPU link, as well as no mention why we split PCIe lanes.
still depends on the board. if the nvme slot has only 2 physical lanes for the drive, it's not going to work at x4 no matter what. but at gen 5, yeah it doesnot need more. this is for high end boards that have full physical lanes on every slot, but can route them at will to whatever they need. not sure there are boards like that for consumers, they are mostly in the enterprise sector.
@The Provoked Prawn Completely unrelated question, but I cant find a concrete answer anywhere else and was hoping you could help - I have just built my first ever PC, and I'm using the latest Corsair iCue Link H150i AIO Cooler for my i9 13900K. My question is which cooling preset do you recommend I use, and is there any negative effect of running the pump at the extreme setting? Would it reduce the lifespan of the pump, for example? Same goes for my fans too, which preset would you recommend for Corsair iCue Link QX RGB fans? Would running them at extreme wear them out quicker? Or is it something I shouldn't really worry about? Much thanks in advance mate.
Sounds like it's running too hot for your liking? I don't know the long term impact of that but there are other things you can do to reduce temps czcams.com/video/jP7nERdD-Gk/video.html
Maybe forcing the pci into gen 4 in bios will allow it to use gen4 nvme and 16 lane for gpu but in pci gen4 instead of 5. i think this is the same for all board that support gen5.
Gen5 uses 8 pcie lanes Gen4 uses 4 pcie lanes. I feel like most people get confused about PCI lanes current intel cpu have 16+4 and depending on your chipset will have more CPU lines. Well, kind of theoretically you have access to them but you can’t run them all at the same time at full speed and if you fill up all the slots up, then you usually lose five and six SATA ports. Typically your graphics card gets 16 One MVME get (x4 gen4 CPU) in your manual, or on the website of your motherboard, where it says specs, it will show you the CPU layout for the CPU lanes. Everything else, depending on the chipset goes through your chipset that means all other SSD,USB devices Bluetooth Wi-Fi and even the bottom 4x slot on your motherboard. That is all controlled by your chipset which has a dedicated line to your CPU. That’s not connected to your 20 PCE lanes directly. That’s why you buy a Z series motherboard because you can typically max everything out. If you have a gen5 motherboard it is using bifurcation for the 20 lanes and if you put a gpu and a gen5 nvme it will run both at x8. Gen5 nvme can’t run x4.
Yes, but only if the GPU is gen 5. Which it isn't. Detailed explanation: bandwidth per lane doubles with each pcie generation. So x8 gen 5 has the same bandwidth as x16 gen 4. But a gen 4 card in a gen 5 slot will only use the lanes at gen 4. Same, a gen 5 card in a gen 4 slot will only use the lanes ar gen 4. The lowest lane speed wins. And 8 lanes are still 8 lanes. Using them at a lower gen does not double the amount of lanes. it just halves the usable bandwidth unfortunately. There are pcie switch chips! These chips can transform for example 8 pcie gen 5 lanes into 16 pcie gen 4 lanes. But that's not something you buy (to my knowledge). Those chips can be on a motherboard that wants more pcie slots than available lanes by the chipset, and sometimes those chips are also used on specialized cards to connect many nvme drives. When quantity of lanes is more important than max speed per lane.
I've read that if the GPU slot is gen 5 it doesn't matter that using the SSD slot halves the lanes on the GPU slot because PCIe gen5 has 2x the lanes of PCIe gen 4 and you're only going to be putting a gen4 GPU in the slot. It's essentially the same as placing it in a PCIe gen 4x16 slot and there aren't any drawbacks to current performance. What do you think of this?
Good vid but not sure I agree with your suggestion to peel off the label off the drive. It is very thin and probably thermally negligible. Also the label is hard to stick back on the drive in case of a warranty claim, as it curls up when you try to re-apply it.
I just bought the asus strix b650-e motherboard it's everything, but and X board without the name. However, this is also gen5, but it states if I use the bottom gen5 nvme slot, that would half the speed of my gpu. I should be able to use the top gen5 slot with no issues. Incidentally, if you did use up the nvme slot that shares the x16 slot, you'll get 8x, but 8x on the gpu lanes won't have any performance impact on a gen4 graphics card.
I have the strix z 790 e ddr5 gaming board and no matter what you do . if you populate the top slot it will always decide the lqin3s with the pcie going to half of its normal x16. Its because the number one slot and pcie lane share the same direct to CPU mains instead of like the rest that go through the chipset.
You can fill the board with NVMe drives and be "fine" on the CPU-Z screen, but you definitely not fine if multiple drives are active at once. With AMD you only get ONE drive connected directly to the CPU and ONE drive connected through the chipset to run at full bandwidth simultaneously without competition. Any drives past that are SHARING those lanes. If more than one drive on the same bus cranks up, speeds on other drives will drop or be halved by default. He says as much in this video. Intel is even worse. No direct CPU bus for an NVMe without robbing GPU lanes, so you only get ONE drive at full speed.
Okay, this may in fact be helpful for ppl that really have no clue about what they are doing and folks that pay attention to PCI-E Lane allocation are simply the wrong audience - especially MSI states the behavior pretty exactly in their manuals, so not really an "hidden problem"! ;-) (i thought this may be something about longjevity of the SSD's or indeed hidden issues with NVMe especially - kinda disapointed it's just about PCI-E allocation wich is a well known "Problem", as it's with EVERY PCI-E device!)
Yes. Users must check the diagram of their motherboard and be aware of the fact that certain ports share bandwidth with other ports. Now, regarding this video, I see no problem in the fact that the M.2 PCIe 5.0 port, when populated, halves the bandwidth of the video card, because it drops it at PCIe 5.0 x8, which is equal to PCIe 4.0 x16. There are no PCIe 5.0 video cards out there yet.
The issue is that both Intel and AMD refuse to put a reasonable number of PCIe lanes on their consumer CPUs. Even where you fill up a board with SSDs, you then just cause a chipset to CPU bottleneck as for example for AM5 the chipset is connected to the CPU by 4 PCIe lanes, so putting a load of drives on the chipset doesn't mean you can access them all at full speed at once.
I heard somewhere online I think that it doesn't matter if the graphics card is limited to x8 pcie because the graphics card doesn't use that bandwith. I also heard of some graphics card coming with an nvme drive bay to make up for the unusued pcie bandwidth.
Not all board steel PCI lanes when using the top M.2 slott, have a Gigabyte Aorus Elite X wifi 7 board its 4.0 x 16 too the grafic card, but the board have no support of gen 5 NVMe drives...
Lanes in use has nothing to do with the PCIe version. Most NVMe drives are 4 lane drives regardless if 3.0, 4.0, or 5.0. As mentioned here, the bifurcation (splitting of x16 CPU lanes to x8/x8) of CPU data lanes is dependent on the MB maker and version of MB has implemented as well as which CPU. It requires a special chip and not all use it. Latest AMD processors have made this worse by having some CPUs in the latest APU line that only allow 4 lanes for a dedicated GPU if added later. This could negatively impact a future GPU added even with the supported PCIe 4.0 version. Also, adding NVMes can disable other ports on the MB. 2 SATA ports often share connectivity with a MB NVMe slot and can be disabled if a NVMe is installed in specific slot. Also, adding a a PCIe card into another x16 length PCIe slot can either run off the chipsets shared bandwidth or restrict the GPU in the first x16 length slot to x8; bifurcation if supported. And finally, NVMes, even if they state in HWInfo as x4, could be hampered in performance if the slot in which the NVMe is inserted is fed from chipset. Typical desktop CPUs have one dedicated NVMe to the CPU x4 lanes. The rest are either stealing from the x16 graphics slot CPU lanes or running through the shared bandwidth of the chipset. This shared bandwidth is with SATA, USB, Ethernet, WiFi, and any other MB "features". The CPU data lanes are limited and unless the device has its own direct memory access and processing unit, it's sharing the CPU lanes with everything else. This only getting more complicated and GPUs and CPUs restrict available lanes of communication.
I think everything would be much easier to explain if you go off the motherboard block diagram, which is in most motherboard's manual. TLDR, there is only so much PCIE lanes to go around with on a consumer platform.
Good vid that said gpu's will not even get close to bottlenecked witn 8x pcie5 lanes unless you run some really wonkey workload. Kind of amusing many high end MB's are having more issues like this since they try co cramp in as much as possible thus bus sharing get more common.
No GPU will run at pcie gen 5 x8 because all modern gpus even the 4090 are gen 4, meaning they will always be slashed down to pcie gen 4 x8, which can lose 3 to 5% max performance. I just ended up putting my gen 4 ssd in the second slot, so my gpu runs full pci4 x16. Sure I lose 2 to 3% max performance off my nvme due to using chipset lanes instead of cpu--but if I have to choose which device to get 100% from: either my $1000 gpu or my $200 ssd, im going to pick the more expensive gpu lol, I want every damn frame I paid for
Have a Gigabyte b550 Aorus Pro AC with a NVME in the top slot. I have confirmed via HWiNFO that GPU is PCIe 4.0 x16. I will be upgrading this PC to a b650 with 7800x3d this week. Hoping I don't run into this issue. I had the same question after looking at the PCIe lane layout but consensus was it does not limit GPU lanes.
News at 11, shared PCIe lanes limit performance when more then one device uses them,... ;) Here's one for you, 4 NVMe drives in a PCIe connected Raid board, when used individually reach full speed, when used in raid zero for speed, they go slower,....
you always have to look at how the PCIe lane are coming off the CPU in retail CPUs which typically share the NVMe and first PCIe slot (for PGU), there is a maximium lanes availabel from the CPU for this purpose but it doesn't matter if you connect a lesser PCI3 standard like 3.0 in either slot. you are still consuming the split between the slots. the other issues is if the GPU actually suffers a performance loss from going to a less than x16 configuration. many GPU don't suffer from a smaller lanes when the version is higher. a PCIex x8 8.0 is the same as PCIe x16 3.0 in terms of bandwidth. plus some GPU are not capible of higher PCIe version which limits the available bandiwdth
I only have my system to reference, but wanted to share that my MSI MAG Z690 TOMAHAWK WIFI DDR4 motherboard has a WD_BLACK SN850 4TB in the first m.2 slot and the EVGA 3080ti 12gb shows to have all 16 lanes accessible in HWiNFO64.
I am running a gen 4 nvme drive in a rog strix Z590-E Gaming Wifi Mobo and my RTX 4090 gets all 16 lanes, I am also running a gen 3 NVME drive. It must depend on your board and mine is a gaming board.
the "pcie halving" problem sounds like not only a motherboard problem, but a CPU problem you are using a CPU that functionally has less PCIe connection than its higher-tier counterparts, and on top of that, your motherboard uses PCIe bifurcation in order to get that 5th gen nvme connectivity
Yeah, but regardless of how many M.2 slots you fill up or not, most GPU's can only utilise no more than 8 lanes from the 16 lane socket on most mobo's.
Don't this effect go back to running out of PCI lanes on the motherboard? There are only so many lanes and they are usually reserved for drives and the GPU but once you start filling them all with M2's and NVME's, the drives take priority and thus removing performance from the GPU. I always thought this was somewhat normal? I have 2 slots on my board and both are full. I haven't noticed a difference in performance since I installed the second one.
I think its very mobo dependent not even manufacturer. My x570 proart halves the second pcie slot as well but not the first slot. What they don't tell you is that the chipset has 4 lanes dedicated to it.
@@TheProvokedPrawn oh even in the owners manual it's not clear I find it hilarious lol. I ended up putting my gen 4 in the top slot and my gen 3 in the slot that uses the chipset 4 lanes.
Our company stopped selling MSI about 10 years ago in Canada anyways. MSI used to be awesome... we sold exclusively MSI for the entire AMD Duron/Athlon era. Then they started putting out garbage and we gave up and sold Asus ever since and had no issues (so far).
my board a PCI gen4 top PCI slot runs at full speed even with a gen4 NVME in top M.2 slot. it is all about knowing what features a board has before you just buy.
Had major issues installling in the top slot on a Asus and Gigabite mobos w/550 chipset. Driver for every device blowing apart, corrupt os with older sata drives. They do not play nice.
The root cause of this is the number of PCIe lanes that the installed CPU has. When a mainboard supports a range of CPUs that vary in the number of PCIe lanes, the design of the motherboard compromises on the connectivity to maximize the use of those available PCIe lanes with respect to the connectivity features of the motherboard. This is more prominent on workstation motherboards that have 7 8/16x PCIe slots. This includes physical PCIe slots that are actually active and PCIe switching that disables PCIe slots or certain interfaces when another is populated (like nVme). This functionality however does reduce the range of motherboards that need to be manufactured and appeals to the budgets of a wider customer market. It would be nice if the the mainboard uEFI BIOS handled this more clearly both as a menu in the console and during POST so users / techs did not have to waste time figuring out what is going on in this scenario. it is really annoying when trying to select a mainboard for a build as these details are generally not available in comparison tables. The uEFI standard has some more growing up to do with respect to this.
I mean, I don’t really need such high speed SSDs, in fact I have two 2Tb SATA SSDs to keep my Steam library on and other stuff and one 1TB NVMe Gen3 for my boot drive, and my PC boots up in like 7 seconds. If you REALLY need so many high speed SSDs then you should buy Threadripper or Xeon for the massively expanded PCIe bandwidth.
Watch out for cheap boards in this respect: on one of these boards, I wanted to install a second M.2, only to find out there was just a single M.2 slot. So I got an expansion card, stuck it in there and plugged the second M.2 in the card. Then I looked at the lane configuration and to my horror I could see the GPU was cut down to 8 x PCIe 3.0 and the SSD was at 4 x PCIe 2.0! The weirdest thing was that the SSD was in a x16 slot, but it was only wired as x4. And that it maxed out at PCIe 2.0. How useless! So better look at the manual, especially when buying a budget board.
3:09 Diagnostic showing that - according to the motherboard - how much potential speed the given drive have has nothing to do with reality. Did you test the performance with all of those drives under full load? I'm pretty sure that won't work. They will reduce their capabilities to keep up with the load.
8x Gen4 lanes is mostly fine for your graphics card. Might get a few % performance penalty. But yeah, not ideal. Too bad there are no Gen5 graphics cards otherwise it wouldn't have been an issue as 8x Gen5 = 16x Gen4 and would've been plenty.
Fortunately, Gen 5 PCIE is comical overkill for almost any application. I think it depends greatly on the motherboard though, as to whether or not you will have some penalty for going with the newest gen speeds - because my ASUS ROG Maximus Z790 Hero - quite similar to the ROG Strix - I currently have 3 NVMe, and I could put 2 more on it - though two of them uses an addon card, I believe I would suffer some penalty - I just can't recall it off the top of my head what it was - pretty sure it would downgrade the number of lanes on one of those channels. I'll need slightly higher capacity than an NVME currently offers for storage of certain things, but I might go back later and put 2 more new NVMe drives into the board just because I can. I've had a good experience with this board - but there are definitely detriments to loading it up with TOO many NVMe drives, or Gen 5 - however, IN PRACTICE (actual use), to my (limited) tests at least, I have not been able to discern a difference at all. If you're going around benchmarking everything in your system, you can see a numbers difference, but a practical difference? nope. At least, not for anything a gamer would be doing. Regardless of where I take that penalty, it would not affect the system's ability to. The only reason I'm not currently is because the other 2 NVMe drives I had from my previous PC build have years of use on them, and I decided to make a secondary computer using them, until they crap out on me. Everything I did with them all installed was still blazingly fast, and I think that's simply because Gen 5 is ...not really something anyone needs - for gaming at least. Your GPU doesn't utilize those Gen 5 lanes, haha... depending on what you have, that too is likely overkill for any gaming that isn't like, 8K (I have a 4090 - yes, I'm one of "those" guys)... It's sure cool to have the option though...! Unfortunately that also jacked the price of all these boards up to an absurd degree... now a motherboard is as expensive as a processor - and if you aren't getting a TOP of the line CPU, you could easily pay more for the motherboard. The motherboard used to be the cheapest piece in a computer outside of maybe Ram or drives - but motherboards also started to become most system's bottleneck. That price tho... ouch. The Z790 boards are absolutely astronomical in price...
well both drives use 4x, doesnt matter what the PCIE version is. i thought this was common sense at this point or is it not common sense. that the GPU would only get 8 lanes vs 12 lanes cause 4 are used by the nvme drive. PCIE lane assignment does not work like that it is either 1x/2x/4x/8x/16x lanes. since that divides up that way, they should use put another nvme slot up there. then you have two getting 4 lanes each and the gpu 8x and then they are not just wasting 4 lanes. with all these things they want to put on the back of motherboards now. they should just put both nvme slots on the back of the board. then find a case with cut outs there for the hs to fit through. on the back would be a good call for a nvme water cooling blocked tied to a 40mmx2 rad. god now i have so many thoughts on cases.
The biggest problem is thermal throttling, i wonder about the longevity of those drives. I will switch to u.2, u.3 or e1.s in the future, this is far more reliable and doesn't have these negative issues. But these board limitations are a complete joke as well
this is why i bought the old asus maximus z790 hero and not the dark hero - in other words just avoid the refresh z790 boards that have top gen5 slot for nvme
This is more an Intel thing then an AMD thing. I can't think of any B650 to X670E motherboard that sacrifices lanes from the 16x slot if the motherboard takes 3 to 4 NVMe drives. I know a couple of boards that can take 5 NVMe drives that share lanes with the 16x PCIe slot. 5 drives is also out of spec!
At 5:44 are U using a program to view all that system info? If so what one? Or is it just the windows 11 default one (I'm still on windows 10 so idk 😂)
Any chance you can read up on or check the Gigabyte TRX50 Aero D. It has 3 PCIE5 slots and 1 PCIE4, and dual PCIE5 x16 gpu slots. I will be running a PCIE4 gpu of course, but have a PCIE5 drive for the main drive. Would really suck if it interferes with the GPU.
Hello. I'm not a brilliant legend like you sir. Can you give me the info on my board? I have the msi b650 carbon wifi. Currently I have a 4080 super installed and a solidigm m.2 in the "gen 5" slot. Thank you.
I have definitely realized over the last couple years that if I am interested in a certain motherboard, I first download the manual for that motherboard and research all of this stuff as there are surprises out there. I have seen in addition to SATA ports being disabled with certain NMVE scenarios, I have also seen Thunderbolt ports disabled in this fashion as well from what I have read in the mobo manuals. Read before you buy is my new mantra!
Nice to see the IRQ sharing and what ports/slots to use on motherboards has grown up.
that's the way to go for since this opportunity exist! (even before manufactures did it themselves, there's still many manual hosting sites online!^^ - hell, ppl even manually scanned pages back in the day to make them public xD)
Yeah, but most manuals don't explain properly how M.2 scenarios work.
@@Matlockization yeah, they are inconsistent with that. Some do, some don't.
@@viperrcr I'm guessing with the high-end boards (or 2025), you can reclaim the dormant 8 lanes from the X16 slot, but it defeats the purpose since most at that price point would spend more on a GPU ??? At least AMD 8700G APU would allow for a free X16 slot for storage provided no GPU installed.
100% of this issue is down to AMD and Intel sitting on the old ways of 24 (20 via CPU and 4 via Chipset) PCIE lanes is enough.
Forcing those who need more lanes to threadripper.
That's exactly what I'm having to go with for my newest build. We need more than 20 lanes...@@richardj163
Not sure about all AM5. But the 7800X3D has 28 lanes total. 4 for chipset and 24 usable. So you can have your whole x16 GPU + x4 M.2 G5 and 4 to spare. And the B650E and X670E chipsets have 36 and 44 usable respectably with 24 been Gen5. The original X670 only had 8. So the X670E that come with PCIe G5 and an M.2 G5 they don't have to split it. They do everything else with the other lanes. Probably why so many boards share M.2 with PCIe slots or Sata ports. Unable to used them all simultaneously. To prevent stealing from the GPU or M.2_1.
This seems to be an intel specific thing. The LGA 1700 is limited to 20 lanes, and only 16 been gen 5, the other 4 are Gen 4. LGA 1851 will address this by having 20 Gen 5, x16 for PCIe slot and x4 for storage. And an aditional 4 Gen 4 lanes. So depending on the manufacture and how they allocate them. There should be boards that can do both at full speed. Asumming the rest of the PCIe slots and M.2 are split between the remaining 4 G4 and the chipset.
@@Omizuke The point is, they took away the dedicated bus lanes for other devices, such as PS/2, USB, Parallel ports, serial ports ,PCI, AGP, IDE, SATA, Onboard Audio, NIC, etc and placed it all on PCIE without expanding the amount of PCIE lanes.
This is why I miss the old enthusiast line of core i7s that used the LGA 2011 socket. Besides having quad channel RAM, those had enough lanes where you could even run a full dual GPU setup using 16x16 lanes, and still had a few to spare. They need to update the enthusiast line and bring it up to full pcie gen 5 spec.
Subscribed, because none of the bigger channels seem to even touch on this topic.
Thanks. I try to cover useful things that not everyone knows.
The same. thank you.
Having been an "Electronics Junkie" for decades, I learned what you cover here the hard way, long ago. (When the going gets weird, the weird turn pro. -Revenge of the Nerds;-) So, I moved up to Threadripper!@@TheProvokedPrawn
Too complicated for gamers. The nvme drives can also run really hot. I only use a single drive in the slot I can easily cool with a extra fan. Usually the bottom slot. There’s not that much real world speed difference for an average user between a nvme and a sata ssd. It’s not like going from a mechanical was.
@@TheProvokedPrawnVery much appreciated
It's daibolical researching this. You literally have to read the manual of every motherboard you're looking to buy.
This was supposed to be easier with AM5, but the B650 and X670 chipsets then got inexplicably split into B650/B650E and X670/X670E which made the whole situation as clear as mud.
Why AMD didn't just say, "B650 is PCIe Gen 4 for everything and X670 is PCIe Gen 5 for main M.2 and first PCIe expansion slot" is a mystery to everyone.
What causes this? Filling up too many PCI lanes? What do you check to see how many devices you can connect without a hit to GPU performance?
@@HardWhereHeroyou just read the manual.
It’s a bitch, but it’s totally possible to gather the information before you make the purchase
You can get kernel instruction pipe issues, cpu affinity, nvme driver code, to the fact that some boards may have one slot(main) apart from 3 slots on a switch before it hits the root complex, or any combo thereof. I'm not saying anything throttles down, but even the test software is baked, based upon the fact that threads rent time on a single instruction queue, assigning workload to any given logical processor. The OS could prioritize your system drive, and assigning workload at that level, start grinding. OSes do go thru kernel and driver updates for said reasons. This is not the first time the hardware has outstripped the OS. I would use one 5.0 drive and leave it at that. Buy the biggest one, not 4 of them because 6 is already specced out. When you're brand new, you're retro.
This revelation blew mind and I've seen all sorts of things over the years; having started building my own PCs back in the x286 days.
Nicely done!
Just be sure to check the GPU with something running. the GPU goes into standby and changes the speed of the PCIe when nothing big is rendering, so that information is not correct if you don't have something actually being processed by the GPU.
That's why on GPUz there's a rendering test near that info.
It changes speed, yes. PCIe lanes, no.
I skipped M2_1 slot for my z790 dark hero because using gen4 still cut my gpu to x8, so I put my system on M2_2 instead, which still connected to the cpu.😅
So that's not a NVMe issue -- but rather a motherboard issue.
That's specifically why I chose the MB i did. I confirmed the last nvme slot piggybacked on a SATA port but did not interfere with the PCIEx16
Which board did you get? as far as I know this is a problem across all Intel boards
@@quatreraberbawinner2628 AMD MSI X670E Carbon
Did you know that most GPU's only use a maximum of 8 out of the 16 lanes ? And the remaining 8 is lost ?
@@Matlockization untrue. Most cards cannot fully saturate 16 lanes of pcie 4/5 yet. However GN and HU have shown the 8 lane budget cards take a performance hit on pcie3 motherboards
@@jasonhenninger8220 GN = GamersNexus ?
Well, all z690/790 boards that have PCIE gen 5 m.2 slot(s) will always halve the first X16 PCIE slot down to X8, regardless of the brand of the board you use.
Even if you install an PCIe 4.0 SSD into the Gen 5 Slot? As far as I know, they share the same physical connection I think?
EDIT: NVM, I should've finished the video before commeting. I only was halfway through it when asking
On the MSI board you can change the generation to 5 in the bios, and use a gen 4 ssd in that slot, and keep all your PCI lanes.
Glad you doing this video. I upgraded my PC from an i7 4790k to a i9 13900k with an Asus Z790 Hero which I thought I could use at full speed with x5 NVME drives. Not so. I've installed 4 now, plan to add a 5th one soon. I think AMD Threadripper has much more M.2/NVME drives slots that any other chipset.
And cost a lot more.
Great video, surprised to see the GPU take a hit with the gen 4 drive. Thanks for exploring this!
Great video!
Thank god these are some very specific high-tier problems, affecting only a tiny minority of users. For example, If you can afford a 700 dollar motherboard, then spend money on bigger SSDs instead of several smaller ones. If you can't afford those SSDs, spend less money on the motherboard. You can get an excellent DDR5 motherboard for $200-300.
Usually, no point in having four or five 1Tb NVMe SSDs in your motherboard. Just buy two 2-4Tb SSDs and be done with it. Also, almost nobody needs these speeds on their SSDs. You don't benefit from it, unless you transfer massive amounts of data on your system regularly, or you do some extreme simulation with huge data amounts (although the work pipeline bottleneck in simulation usually is not the data transfer rate of an SSD, but the CPU, unless you're using a $20k super home computer with 2 physical CPUs with 128 cores both, or something like that).
Only 0.1% of PC users will actually benefit from the PCIe 5.0x4 (4 lanes, 4GB/lane) 16 GB/s data transfer speed compared to the 8 GB/s speed on PCIe 4.0x4 (4 lanes, 2GB/lane), so the 99.99% of us peasants are doing just great with the PCIe 4.0 speeds. Gaming doesn't benefit from the extra speed at all, and even heavy video editing or most productivity workloads doesn't benefit from it. The work pipeline bottleneck is pretty much always elsewhere.
Very good points, NVMe lane splitting can be an issue. Larger NVMe will also spread I/o across more chips on the drive.
"Almost nobody needs these speeds on their SSDs" lol. ALL PC gamers need those speeds. Games are bigger and more texture rich than ever to the point that SATA SSDs and slower NVMe drives are falling behind. NVMe drives show very noticeable gains in loading times with newer games even without specific optimization. Any games with Direct Storage show massive gains. Some games like Ratchet and Clank have fundamental changes in gameplay based on your drive speed.
very helpful information. I did a lot of research on my board and drives before pulling the trigger to purchase. I'll make sure to reference this video when I need to assist others
The motherboard manuals show how the lanes are divided. From what ive seen on many AM5 boards, the top nvme slot steals lanes (which goes against the meta we've been accustomed to for the past few years)
It's not really an issue with NVme, it's an issue with Intel stupid lane allocation/sharing (and lack of lanes). AM5 is quite better in this aspect
I believe the Asrock X670-E Taichi runs the PCIe gen 5 NVME through the chipset, allowing the PCIe x16 for the GPU to run uninterrupted to the CPU, unless of course you use the second PCIe slot.
I have an ASRock X670E Pro RS and can fill all the m.2 slots and still get 16x Gen 4 for the GPU, depends on the CPU and motherboard type, if the motherboard has it's own controller chip for M.2 drives I think it frees up some lanes from the CPU.
controller chips still need pci-e lanes to connect with the cpu. what the issue is, you can have all your nvme's connected and r/w at max speeds, the chipset bandwidth is limited. so tranferring data from all of them at the same time doesnot addup because the chipset has to share the bandwidth with every device it has. it's a common misconception, the fact that the drives are working at full speed, doesnot mean that the data are going to the cpu at that rate.
You definately gave me something to think about. I've got an open NVME spot and was gonna buy another drive while I had some extra money. Now I gotta see what impact that will have on my board. Asus PRIME Z790-P WIFI ATX LGA1700. Wasn't going to choose it, but it was part of a bundel at Micro Center, and a great deal price.
This has been a problem for years. I Used an MSI x370 gaming carbon pro and the second nvme slot disabled one of the SAT slots if a NVME was fitted. The PCIE slot 4 was only 4 lanes but it ran my EX570 woth no problems and I got a 4 nvme addon card which I used in the PCiE 16 lanes.
I wanted to go to a MATX and Ryzen 5700G thinking I could use the 4 way card for 4 NVME drives by making the PCIE slot 1 into a 4x4x4x4. No the Ryzen 5700G only supports 8x4x4 so thats t nvme drives. The Board us an Asrock b550 pro 4. I was aware the second nvme position only operated at PCIE2 if used as nvme and also disabled a SATA position. I knew the Ryzen 5700G was only PCIE 3 but that did not bother me. I was counting on using the 4 port nvme card in the PCIE 16 lane running 4x4x4x4. But as noted above the ryxen 5700g will not do that. I think its rather stupid of AMD not to think a user of integrated graphics might want to use the graphics slot for something else. I am now tied to noo graphic card in this system as I am fitting a 2 port nvme adapter with a chip card into the second long pcie slot that runs 4 lanes.
The whole thing of what happens is not documented well by anyone.
I have the same board and only use the top drive and get x16 on my 4090. So it might not be what you think? Maybe if you fill all with gen 4s or just top with gen 5 it locks it to 8x.
It would be handy to show us how to read a motherboard schematic - to show if the M.2 is stealing lanes or not.
chips only have a limited number of specific generation PCIe lanes, you can also have PCIe switches on a board that will split up a higher gen lane to multiple lower gen lanes, but this isn't always the case.
for the i9-13900k that has 20 PCIe lanes maximum and support gen 4 and gen 5 in the following configuration 'Up to 1x16+4, 2x8+4'
So, uh, question: Have you tried checking the lane usage while actually USING the graphics card for something? To see if it is prioritizing bandwidth to the gpu when it is going full tilt, but leaving it in a lower bandwidth mode when it isn't using that bandwidth? Obviously, test while gen5 slot is idle, but might be something worth checking.
It's also a good thing to remember that for most consumer uses, an NVME doesn't provide much, if any, noticeable benefit over a SATA SSD. So you can usually just whack a Sata ssd in instead of using that gen 5 slot.
Also, yes, always a good idea to check the specs of parts BEFORE purchasing them by looking at the more detailed data available on manufacturer's site, instead of just marketing slides. It's helpful for pretty much EVERY part.
An LGA1700 CPU offers 20 CPU PCIe lanes. This includes 16 PCIe 5.0 lanes and 4 PCIe 4.0 lanes. If the motherboard designer chooses to employ PCIe 5.0 for the primary ("top slot") SSD, those lanes must be borrowed from the lanes allocated to the GPU, so the GPU gets 8 lanes, the SSD gets 4 lanes, and 4 lanes (of the 16 allocated to the GPU) will go unused. Even when a PCIe 4.0 SSD is installed in the top slot, the board's architecture is still employing 4 lanes from the GPU, so the GPU will get only 8 lanes. If you want your GPU to have 16 PCIe 5.0 lanes on a board like this, you need to leave the top slot unpopulated. Intel's upcoming 15th gen Arrow Lake (LGA1851) will remedy this by increasing the PCIe 5.0 lanes from 16 to 20 (in addition to the 4 lanes of PCIe 4.0).
I always love the details you put in your videos. thanks for continuing to make great content
Thank you. Appreciate your support
I need to download this program now. My motherboard only has two NVMe slots, but I was warned this might be an issue since it's a cheap board.
The sticker on NVME SSDs actually serves a purpose by transferring heat from the controller to the NAND chips, which need the temperature to work well.
With the mpg z790 edge TI Max wifi, it explicitly states in the instructions that if m.2 slot 1 is used, it will knock your x16 gpu slot to x8. This is because the #1 m.2 shares the same bus as the x16 slot, which is shared directly with the CPU itself. If you want to make full use of your gpu, leave m.2 slot 1 empty. Also, if you use the m.2 slot 3, your sata data 1 & 2 is useless. Same principle with the exception that m.2 slots 2-5 are managed through the z790 chipset. That chipset mangages other secondary interfaces as well. These technical phenomenons are common place and are mentioned in CompTIA a+
I really like my MSI board for NVMEs it's a B550 tomahawk. It actually lets you decide how you want the lanes split... kind of. 8+8, or 8+4+4, 4+4+4+4 and then everything is full. Mine is currently 8+8 cause I'm just using 1 NVME so everything is nice and quick. I will be upgrading eventually so I'll dumb it down to 8+4+4 but my GPU will still be full speed while the NVMEs get to share. That being said it doesn't have a thermal pad on the board side like yours does! It has the heatsinks for the top if the NVME doesn't have its own (mine does) but nothing for underneath.
I`m not suprised by this, i did notice however that even on MSI`s webpage for this Z790 motherboards specs and even in it`s manual it nowhere mentions the sharing of pcie lanes, wonder if you have bandwith bifurication option in the bios on this board.
these kind of issue`s is the reason for me why i went with a AMD 7950X and a X670e board. 1. amd gets you 28 pcie lanes instead of intel with 20 lanes
2. X670e gets you a lot of additional pcie 4.0 lanes.
i can easily install 5 nvme`s of which 1 is pcie 5.0 and still have pciex16_1 slot run x16.
I JUST got a couple new drives to fill the last couple spots on my board. Haven't noticed any problems, but also didn't know this was a possibility so haven't checked...
I was having this problem and didn't even realize it. Thank you!
No worries
It's still oversubscribed, five SSD need 20 lanes but they have to share four PCIe 4.0 lanes and eight DMI 16GT/s lanes at the CPU. If the drives are used simultaneously it might be better to split the x16 slot for a Gen 5 SSD. This is one area where AMD is more flexible, you can have up to 5x Gen5 SSD, and only 2x on Intel
Before buying any motherboard, download and thoroughly read the motherboard instructions, as most do describe the limitations and trade-off in propagating the different types of data storage/transfer ports, it saves on time, money and broken expectations; laziness and or rushing are often the cause of so much heartbreak!
If you’re running an 12th, 13th or 14th gen Intel cpu, and a z790 motherboard, you get 20 lanes on the cpu, so 16 for the graphic card and 4 for the M.2. That then leaves you 20 lanes on the chipset, which can handle upto 5 gen 4 M.2. Only becomes an issue, if you start using any of the other pcie slots
Yes this is all True. I've been building my own Gaming configurations for 40 years. I currently use the Asus ROG Strix B550 XE Gaming Motherboard & 2 TB NVME M.2 SSD Ryzen 7 5800X CPU. Yes installing another M.2 in the lower slot will split the Lane Traffic to half. Instead of 16X they will both be 8X.
How do you research this? Will it state somewhere in the specs? I understand how to test once you have the parts, but id obviously like to know before purchasing
It should hopefully be in the specs, the manual or the pcie bifurcation table
@@TheProvokedPrawn I've looked into this a bit (actually how I found your original video) and as far as I can tell this is a problem across all Intel motherboards, at the very least the z790 ones
All you need to know, is how PCIe lanes are distributed.
You can divide PCIe lanes (usually done to CPU lanes), or create new ones ( chipset ), but if there’s not enough, you can disable some of them.
The problem is simple, cost.
There was also no mention of max speed of chipset to CPU link, as well as no mention why we split PCIe lanes.
Hybrid PCIe M.2 drives are the future IMO (i'm talking about the new PCIe 5.0 x2 drives that also work as PCIe 4.0 x4)
Rather more of a temporary solution until Intel and AMD add more PCIe lanes to their consumer products.
still depends on the board. if the nvme slot has only 2 physical lanes for the drive, it's not going to work at x4 no matter what. but at gen 5, yeah it doesnot need more. this is for high end boards that have full physical lanes on every slot, but can route them at will to whatever they need. not sure there are boards like that for consumers, they are mostly in the enterprise sector.
@The Provoked Prawn Completely unrelated question, but I cant find a concrete answer anywhere else and was hoping you could help - I have just built my first ever PC, and I'm using the latest Corsair iCue Link H150i AIO Cooler for my i9 13900K.
My question is which cooling preset do you recommend I use, and is there any negative effect of running the pump at the extreme setting? Would it reduce the lifespan of the pump, for example?
Same goes for my fans too, which preset would you recommend for Corsair iCue Link QX RGB fans? Would running them at extreme wear them out quicker? Or is it something I shouldn't really worry about?
Much thanks in advance mate.
Sounds like it's running too hot for your liking? I don't know the long term impact of that but there are other things you can do to reduce temps czcams.com/video/jP7nERdD-Gk/video.html
Maybe forcing the pci into gen 4 in bios will allow it to use gen4 nvme and 16 lane for gpu but in pci gen4 instead of 5. i think this is the same for all board that support gen5.
sooo so many things to look out for when purchasing a mobo its insane, and most of the stuff you can see only in the manual when its too late.
Most manuals are available on the website in a PDF you can typically read before you buy
Great vid, you got my sub. Cool voice as well, makes learning much easier.
Awesome, thank you!
Gen5 uses 8 pcie lanes Gen4 uses 4 pcie lanes. I feel like most people get confused about PCI lanes current intel cpu have 16+4 and depending on your chipset will have more CPU lines. Well, kind of theoretically you have access to them but you can’t run them all at the same time at full speed and if you fill up all the slots up, then you usually lose five and six SATA ports. Typically your graphics card gets 16 One MVME get (x4 gen4 CPU) in your manual, or on the website of your motherboard, where it says specs, it will show you the CPU layout for the CPU lanes. Everything else, depending on the chipset goes through your chipset that means all other SSD,USB devices Bluetooth Wi-Fi and even the bottom 4x slot on your motherboard. That is all controlled by your chipset which has a dedicated line to your CPU. That’s not connected to your 20 PCE lanes directly. That’s why you buy a Z series motherboard because you can typically max everything out. If you have a gen5 motherboard it is using bifurcation for the 20 lanes and if you put a gpu and a gen5 nvme it will run both at x8. Gen5 nvme can’t run x4.
If your gpu is inserted in a gen 5 slot but x8 lanes, isnt that the same as gen4 x16?
Yes, but only if the GPU is gen 5. Which it isn't.
Detailed explanation:
bandwidth per lane doubles with each pcie generation. So x8 gen 5 has the same bandwidth as x16 gen 4.
But a gen 4 card in a gen 5 slot will only use the lanes at gen 4. Same, a gen 5 card in a gen 4 slot will only use the lanes ar gen 4. The lowest lane speed wins.
And 8 lanes are still 8 lanes. Using them at a lower gen does not double the amount of lanes. it just halves the usable bandwidth unfortunately.
There are pcie switch chips! These chips can transform for example 8 pcie gen 5 lanes into 16 pcie gen 4 lanes. But that's not something you buy (to my knowledge). Those chips can be on a motherboard that wants more pcie slots than available lanes by the chipset, and sometimes those chips are also used on specialized cards to connect many nvme drives. When quantity of lanes is more important than max speed per lane.
Yes it is the same as gen4
i was expecting you talk about some nvme diagnostic tools or namespaces or 4k LBA size
Read the specs for your motherboard carefully before filling up with nvme drives.
Dont assume anything - go by the specs.
I've read that if the GPU slot is gen 5 it doesn't matter that using the SSD slot halves the lanes on the GPU slot because PCIe gen5 has 2x the lanes of PCIe gen 4 and you're only going to be putting a gen4 GPU in the slot. It's essentially the same as placing it in a PCIe gen 4x16 slot and there aren't any drawbacks to current performance. What do you think of this?
I tested and there was minimal negative impact czcams.com/video/CT55vgeuhPo/video.html
@@TheProvokedPrawn Is the PCIe slot you're using in that video gen 5 or gen 4?
Good vid but not sure I agree with your suggestion to peel off the label off the drive. It is very thin and probably thermally negligible. Also the label is hard to stick back on the drive in case of a warranty claim, as it curls up when you try to re-apply it.
I removed mine and i saw significant improvement. 5c+
I didn't say to peel it, in fact I'd say not to. czcams.com/video/BmqcKBwOwRc/video.html
I just bought the asus strix b650-e motherboard it's everything, but and X board without the name. However, this is also gen5, but it states if I use the bottom gen5 nvme slot, that would half the speed of my gpu. I should be able to use the top gen5 slot with no issues. Incidentally, if you did use up the nvme slot that shares the x16 slot, you'll get 8x, but 8x on the gpu lanes won't have any performance impact on a gen4 graphics card.
I have the strix z 790 e ddr5 gaming board and no matter what you do . if you populate the top slot it will always decide the lqin3s with the pcie going to half of its normal x16. Its because the number one slot and pcie lane share the same direct to CPU mains instead of like the rest that go through the chipset.
You can fill the board with NVMe drives and be "fine" on the CPU-Z screen, but you definitely not fine if multiple drives are active at once. With AMD you only get ONE drive connected directly to the CPU and ONE drive connected through the chipset to run at full bandwidth simultaneously without competition. Any drives past that are SHARING those lanes. If more than one drive on the same bus cranks up, speeds on other drives will drop or be halved by default. He says as much in this video. Intel is even worse. No direct CPU bus for an NVMe without robbing GPU lanes, so you only get ONE drive at full speed.
Okay, this may in fact be helpful for ppl that really have no clue about what they are doing and folks that pay attention to PCI-E Lane allocation are simply the wrong audience - especially MSI states the behavior pretty exactly in their manuals, so not really an "hidden problem"! ;-)
(i thought this may be something about longjevity of the SSD's or indeed hidden issues with NVMe especially - kinda disapointed it's just about PCI-E allocation wich is a well known "Problem", as it's with EVERY PCI-E device!)
Yes.
Users must check the diagram of their motherboard and be aware of the fact that certain ports share bandwidth with other ports.
Now, regarding this video, I see no problem in the fact that the M.2 PCIe 5.0 port, when populated, halves the bandwidth of the video card, because it drops it at PCIe 5.0 x8, which is equal to PCIe 4.0 x16.
There are no PCIe 5.0 video cards out there yet.
The issue is that both Intel and AMD refuse to put a reasonable number of PCIe lanes on their consumer CPUs.
Even where you fill up a board with SSDs, you then just cause a chipset to CPU bottleneck as for example for AM5 the chipset is connected to the CPU by 4 PCIe lanes, so putting a load of drives on the chipset doesn't mean you can access them all at full speed at once.
I heard somewhere online I think that it doesn't matter if the graphics card is limited to x8 pcie because the graphics card doesn't use that bandwith. I also heard of some graphics card coming with an nvme drive bay to make up for the unusued pcie bandwidth.
What everyone forgets is what happens when you put an 8x pcie4 GPU in a pcie3 slot. 16 to 8 is still fine but not 8 to 4.
And now may checking if the x8 any Impact the GPU in any way (gaming in focus)
On the Asus rog B350 f gaming ... When you use the nvme slot, the sata 5 and 6 will be disabled automatically
Not all board steel PCI lanes when using the top M.2 slott, have a Gigabyte Aorus Elite X wifi 7 board its 4.0 x 16 too the grafic card, but the board have no support of gen 5 NVMe drives...
Lanes in use has nothing to do with the PCIe version. Most NVMe drives are 4 lane drives regardless if 3.0, 4.0, or 5.0. As mentioned here, the bifurcation (splitting of x16 CPU lanes to x8/x8) of CPU data lanes is dependent on the MB maker and version of MB has implemented as well as which CPU. It requires a special chip and not all use it. Latest AMD processors have made this worse by having some CPUs in the latest APU line that only allow 4 lanes for a dedicated GPU if added later. This could negatively impact a future GPU added even with the supported PCIe 4.0 version. Also, adding NVMes can disable other ports on the MB. 2 SATA ports often share connectivity with a MB NVMe slot and can be disabled if a NVMe is installed in specific slot. Also, adding a a PCIe card into another x16 length PCIe slot can either run off the chipsets shared bandwidth or restrict the GPU in the first x16 length slot to x8; bifurcation if supported. And finally, NVMes, even if they state in HWInfo as x4, could be hampered in performance if the slot in which the NVMe is inserted is fed from chipset. Typical desktop CPUs have one dedicated NVMe to the CPU x4 lanes. The rest are either stealing from the x16 graphics slot CPU lanes or running through the shared bandwidth of the chipset. This shared bandwidth is with SATA, USB, Ethernet, WiFi, and any other MB "features". The CPU data lanes are limited and unless the device has its own direct memory access and processing unit, it's sharing the CPU lanes with everything else. This only getting more complicated and GPUs and CPUs restrict available lanes of communication.
I think everything would be much easier to explain if you go off the motherboard block diagram, which is in most motherboard's manual. TLDR, there is only so much PCIE lanes to go around with on a consumer platform.
Good vid that said gpu's will not even get close to bottlenecked witn 8x pcie5 lanes unless you run some really wonkey workload. Kind of amusing many high end MB's are having more issues like this since they try co cramp in as much as possible thus bus sharing get more common.
No GPU will run at pcie gen 5 x8 because all modern gpus even the 4090 are gen 4, meaning they will always be slashed down to pcie gen 4 x8, which can lose 3 to 5% max performance. I just ended up putting my gen 4 ssd in the second slot, so my gpu runs full pci4 x16.
Sure I lose 2 to 3% max performance off my nvme due to using chipset lanes instead of cpu--but if I have to choose which device to get 100% from: either my $1000 gpu or my $200 ssd, im going to pick the more expensive gpu lol, I want every damn frame I paid for
Have a Gigabyte b550 Aorus Pro AC with a NVME in the top slot. I have confirmed via HWiNFO that GPU is PCIe 4.0 x16. I will be upgrading this PC to a b650 with 7800x3d this week. Hoping I don't run into this issue. I had the same question after looking at the PCIe lane layout but consensus was it does not limit GPU lanes.
News at 11, shared PCIe lanes limit performance when more then one device uses them,... ;)
Here's one for you, 4 NVMe drives in a PCIe connected Raid board, when used individually reach full speed, when used in raid zero for speed, they go slower,....
you always have to look at how the PCIe lane are coming off the CPU in retail CPUs which typically share the NVMe and first PCIe slot (for PGU), there is a maximium lanes availabel from the CPU for this purpose but it doesn't matter if you connect a lesser PCI3 standard like 3.0 in either slot. you are still consuming the split between the slots. the other issues is if the GPU actually suffers a performance loss from going to a less than x16 configuration. many GPU don't suffer from a smaller lanes when the version is higher. a PCIex x8 8.0 is the same as PCIe x16 3.0 in terms of bandwidth. plus some GPU are not capible of higher PCIe version which limits the available bandiwdth
I only have my system to reference, but wanted to share that my MSI MAG Z690 TOMAHAWK WIFI DDR4 motherboard has a WD_BLACK SN850 4TB in the first m.2 slot and the EVGA 3080ti 12gb shows to have all 16 lanes accessible in HWiNFO64.
Because it only has pcie gen 4 support for m. 2, there is no gen 5.
I am running a gen 4 nvme drive in a rog strix Z590-E Gaming Wifi Mobo and my RTX 4090 gets all 16 lanes, I am also running a gen 3 NVME drive. It must depend on your board and mine is a gaming board.
It does
the "pcie halving" problem sounds like not only a motherboard problem, but a CPU problem
you are using a CPU that functionally has less PCIe connection than its higher-tier counterparts, and on top of that, your motherboard uses PCIe bifurcation in order to get that 5th gen nvme connectivity
Yeah, but regardless of how many M.2 slots you fill up or not, most GPU's can only utilise no more than 8 lanes from the 16 lane socket on most mobo's.
Don't this effect go back to running out of PCI lanes on the motherboard? There are only so many lanes and they are usually reserved for drives and the GPU but once you start filling them all with M2's and NVME's, the drives take priority and thus removing performance from the GPU. I always thought this was somewhat normal? I have 2 slots on my board and both are full. I haven't noticed a difference in performance since I installed the second one.
I think its very mobo dependent not even manufacturer. My x570 proart halves the second pcie slot as well but not the first slot. What they don't tell you is that the chipset has 4 lanes dedicated to it.
yeah it varies wildly and it's not made clear. Hence why I wanted to highlight these things :)
@@TheProvokedPrawn oh even in the owners manual it's not clear I find it hilarious lol. I ended up putting my gen 4 in the top slot and my gen 3 in the slot that uses the chipset 4 lanes.
Our company stopped selling MSI about 10 years ago in Canada anyways. MSI used to be awesome... we sold exclusively MSI for the entire AMD Duron/Athlon era. Then they started putting out garbage and we gave up and sold Asus ever since and had no issues (so far).
I would wish to have only these kinds of problems.
1:45 I have that pac-man stress ball too
That's actually a light
@TheProvokedPrawn cool, it looks exactly like my stress ball
The stickers are not meant to cause any heat transfer problems according to the manufacturers
my board a PCI gen4 top PCI slot runs at full speed even with a gen4 NVME in top M.2 slot. it is all about knowing what features a board has before you just buy.
Had major issues installling in the top slot on a Asus and Gigabite mobos w/550 chipset. Driver for every device blowing apart, corrupt os with older sata drives.
They do not play nice.
That's why I went with a Ryzen, using a x670e dual chip set mobo.
The root cause of this is the number of PCIe lanes that the installed CPU has.
When a mainboard supports a range of CPUs that vary in the number of PCIe lanes, the design of the motherboard compromises on the connectivity to maximize the use of those available PCIe lanes with respect to the connectivity features of the motherboard. This is more prominent on workstation motherboards that have 7 8/16x PCIe slots.
This includes physical PCIe slots that are actually active and PCIe switching that disables PCIe slots or certain interfaces when another is populated (like nVme).
This functionality however does reduce the range of motherboards that need to be manufactured and appeals to the budgets of a wider customer market.
It would be nice if the the mainboard uEFI BIOS handled this more clearly both as a menu in the console and during POST so users / techs did not have to waste time figuring out what is going on in this scenario.
it is really annoying when trying to select a mainboard for a build as these details are generally not available in comparison tables.
The uEFI standard has some more growing up to do with respect to this.
I mean, I don’t really need such high speed SSDs, in fact I have two 2Tb SATA SSDs to keep my Steam library on and other stuff and one 1TB NVMe Gen3 for my boot drive, and my PC boots up in like 7 seconds. If you REALLY need so many high speed SSDs then you should buy Threadripper or Xeon for the massively expanded PCIe bandwidth.
Watch out for cheap boards in this respect: on one of these boards, I wanted to install a second M.2, only to find out there was just a single M.2 slot. So I got an expansion card, stuck it in there and plugged the second M.2 in the card. Then I looked at the lane configuration and to my horror I could see the GPU was cut down to 8 x PCIe 3.0 and the SSD was at 4 x PCIe 2.0!
The weirdest thing was that the SSD was in a x16 slot, but it was only wired as x4. And that it maxed out at PCIe 2.0. How useless!
So better look at the manual, especially when buying a budget board.
3:09 Diagnostic showing that - according to the motherboard - how much potential speed the given drive have has nothing to do with reality. Did you test the performance with all of those drives under full load? I'm pretty sure that won't work. They will reduce their capabilities to keep up with the load.
Yes I tested too
8x Gen4 lanes is mostly fine for your graphics card. Might get a few % performance penalty. But yeah, not ideal. Too bad there are no Gen5 graphics cards otherwise it wouldn't have been an issue as 8x Gen5 = 16x Gen4 and would've been plenty.
Between the Asus and MSI MOBO, which do you think is better when it comes to gaming and overall performance?
Google is your friend.
Wasn't asking you, mind your own business.@@repairman2be250
Fortunately, Gen 5 PCIE is comical overkill for almost any application. I think it depends greatly on the motherboard though, as to whether or not you will have some penalty for going with the newest gen speeds - because my ASUS ROG Maximus Z790 Hero - quite similar to the ROG Strix - I currently have 3 NVMe, and I could put 2 more on it - though two of them uses an addon card, I believe I would suffer some penalty - I just can't recall it off the top of my head what it was - pretty sure it would downgrade the number of lanes on one of those channels. I'll need slightly higher capacity than an NVME currently offers for storage of certain things, but I might go back later and put 2 more new NVMe drives into the board just because I can.
I've had a good experience with this board - but there are definitely detriments to loading it up with TOO many NVMe drives, or Gen 5 - however, IN PRACTICE (actual use), to my (limited) tests at least, I have not been able to discern a difference at all. If you're going around benchmarking everything in your system, you can see a numbers difference, but a practical difference? nope. At least, not for anything a gamer would be doing. Regardless of where I take that penalty, it would not affect the system's ability to. The only reason I'm not currently is because the other 2 NVMe drives I had from my previous PC build have years of use on them, and I decided to make a secondary computer using them, until they crap out on me. Everything I did with them all installed was still blazingly fast, and I think that's simply because Gen 5 is ...not really something anyone needs - for gaming at least. Your GPU doesn't utilize those Gen 5 lanes, haha... depending on what you have, that too is likely overkill for any gaming that isn't like, 8K (I have a 4090 - yes, I'm one of "those" guys)... It's sure cool to have the option though...!
Unfortunately that also jacked the price of all these boards up to an absurd degree... now a motherboard is as expensive as a processor - and if you aren't getting a TOP of the line CPU, you could easily pay more for the motherboard. The motherboard used to be the cheapest piece in a computer outside of maybe Ram or drives - but motherboards also started to become most system's bottleneck.
That price tho... ouch. The Z790 boards are absolutely astronomical in price...
well both drives use 4x, doesnt matter what the PCIE version is. i thought this was common sense at this point or is it not common sense. that the GPU would only get 8 lanes vs 12 lanes cause 4 are used by the nvme drive. PCIE lane assignment does not work like that it is either 1x/2x/4x/8x/16x lanes. since that divides up that way, they should use put another nvme slot up there. then you have two getting 4 lanes each and the gpu 8x and then they are not just wasting 4 lanes.
with all these things they want to put on the back of motherboards now. they should just put both nvme slots on the back of the board. then find a case with cut outs there for the hs to fit through. on the back would be a good call for a nvme water cooling blocked tied to a 40mmx2 rad. god now i have so many thoughts on cases.
can you tell the difference between a gen 4 and gen 5 drive as a gamer?
Probably not
The biggest problem is thermal throttling, i wonder about the longevity of those drives. I will switch to u.2, u.3 or e1.s in the future, this is far more reliable and doesn't have these negative issues. But these board limitations are a complete joke as well
this is why i bought the old asus maximus z790 hero and not the dark hero - in other words just avoid the refresh z790 boards that have top gen5 slot for nvme
just checked my gigabyte z790 elite ax x motherboard with a gen 4 nvme in the top slot my gpu is PCIe v4.0 x8 (16.0 GT/s) @ x8 (16.0 GT/s) cut to x8
My rtx 4070 laptop msi b12v is only running @x8 is that normal for laptop or?
This is more an Intel thing then an AMD thing.
I can't think of any B650 to X670E motherboard that sacrifices lanes from the 16x slot if the motherboard takes 3 to 4 NVMe drives.
I know a couple of boards that can take 5 NVMe drives that share lanes with the 16x PCIe slot. 5 drives is also out of spec!
If money isnt an option, is 670 meg ace better then 670 aorus master ?
At 5:44 are U using a program to view all that system info? If so what one? Or is it just the windows 11 default one (I'm still on windows 10 so idk 😂)
Looks like HWInfo
HWinfo64
Any chance you can read up on or check the Gigabyte TRX50 Aero D. It has 3 PCIE5 slots and 1 PCIE4, and dual PCIE5 x16 gpu slots. I will be running a PCIE4 gpu of course, but have a PCIE5 drive for the main drive. Would really suck if it interferes with the GPU.
based on the manual from the website on page 24 and 25, seems like it wont sharing lane so no issue it will be disabled. so should be no issue
lanes are lanes, 2.0 5.0 doesn't mattes if it asks for 4 it gets 4.
Hello. I'm not a brilliant legend like you sir. Can you give me the info on my board? I have the msi b650 carbon wifi. Currently I have a 4080 super installed and a solidigm m.2 in the "gen 5" slot. Thank you.
still interesting that the i9 14900k only have 20 PEcie Lanes, even my i7 3930k have 40 Pcie Lanes (with a little mod even in PCIe 3.0 speed)