Cheap SD Cards? Why and How You Should Test Your Memory Cards

EPISODE 33
Fake or Real? You can find some great prices on SD memory cards online, but sometimes these prices seem too good to be true. In this episode we explain how to test and verify that your memory cards are living up to their advertised speeds and capacities.
00:00 - Start
01:17 - Speed Ratings
02:00 - Bus Speed
02:18 - UHS-I vs UHS-II
05:21 - MKING Card Test
09:00 - TOTASD Card Test
10:24 - Lexar Card Test
11:16 - SanDisk Card Test
12:57 - Summary
Mac - Download Blackmagic Disk Speed Test from the App Store:
apps.apple.com/us/app/blackma...
Windows - Blackmagic Disk Speed Test is part of Blackmagic Desktop Video - Download and install Blackmagic Desktop Video:
www.blackmagicdesign.com/supp...
Learn more about SD Card speed classes:
www.sdcard.org/developers/sd-...
Learn more about SD Card buss speed:
www.sdcard.org/developers/sd-...
Presented by
Tony Tang - Instagram: @tonytangpro
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Follow The Three Techs on Twitter: @thethreetechs
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Follow The Three Techs on Instagram: @thethreetechs
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[@agrotani151]

A Big Eye opening.. thanks, really help 🙂👍👍

[@moondrums]

This is very helpful. new subscriber. great vid.

[@PhotoTrekr]

I wouldn't expect a no name card to be reliable or truthful about the speeds.

[@AlastorShadow0]

the blackmagic tester is not for windows is it?

[@exFatigue]

Thanks for this. I recently bought 3 SanDisk Extreme Pro cards from eBay which I tested using tools suggested by your video & all turned out to be fake! The cards and packaging were identical to the genuine article!

[@PhotoTrekr]

Yep. Bootleggers have gotten pretty good at making fakes. Choose a reputable seller next time like B&H.

[@markjohnson9402]

The old adage, you get what you pay for. Never truer than when dealing with SD cards, ; )

[@DD-jk3nf]

Yeah that's not how to test SD cards lol and you were completely shooting in the dark with the reliability/data corruption bit. There was no need to reiterate the one/two rows thing 346 times. These are simply dodgy cards that have been sold on market places for donkeys years now.
For anyone that is encountering this kind of thing. There are utilities that will test flash storage devices (RMPrepUSB and h2testw are two popular ones). What was put down to reliability/data corruption in the video is not what is happening. An SD card contains a block storage device (just like a flash chip, hard drive, an ssd or however you'd like visualize it) with a microcontroller to act as a middleman between the host (the computer/device) and the storage. That microcontroller has its own firmware and that's where the magic happens. One of the things the microcontroller will do is advertise to the host the capabilities of the card, including the card capacity. The operating system using the card may be told (for examples sake) that the card is 128GB, when in reality the card capacity may only be 64GB. When more than 64GB is written to the card the new data starts overwriting previously written data (the addresses wrap and the new data goes back to the beginning). The card and host are doing exactly what they are supposed to do. So if you wrote something like a video file to the card, you may see that video stuttering or not even loading at all. That is entirely dependant on the video encoding type used in the file but that's a different subject.
There aren't that many manufacturers of flash storage so the flash used in those dodgy cards is really just as good as any other. Flash has a maximum (guaranteed) amount of write cycles each cell can written to so providing the card is new, reliability isn't a concern. What people are doing is they get access to the systems in the factories that produce SD cards, which includes the gang programmers that can write the cards firmware. They take a huge batch of of older cards that were never sold, they stick a firmware on them that advertises a larger capacity then chuck them through the printing systems and there you go, a load of freshly produced 'fake' cards. Unfortunately many of the people that run the factories don't give a monkeys crap what staff are doing out of hours.
The thing is with these cards, many of them will be your top branded cards, just older ones, modified and rebranded. Now you can still use these cards and they'll work just fine. Use a good utility that will do block write/verify test to find out what the real capacity of the card is. Then wipe the cards partition(s) and create a new partition starting at the beginning of the drive that is the real capacity of the card. After that the card will work fine as it will never try to write to an area that doesn't really exist (so it won't wrap back to the first addresses on the card).
The speed of course can't do anything about, it's just an older card. What wasn't mentioned at all in the video is the device you are using to access the card and this can make a world of difference. The adapter you use to read the card can create a serious bottleneck. Many USB card readers are slow and that includes the readers built into laptops. Just because the laptop has a dedicated slot for SD cards doesn't mean it's any better than a crappy couple of bucks USB reader. A cheap option for laptop manufacturers for putting an SD slot in the system is just to build a USB adapter right onto the mainboard and it might not be a good one. That can go the other way though, that built in SD interface might be a top end full blown pci-e card built onto the mainboard or are speedy good quality USB3 reader. The main thing is just keep the SD interface itself in mind when testing cards.

[@scremingwhisper1720]

H2Testw