Having played with "lower simulation update rate" for 2 days, I would advise to not activate this option. The INS degrades pretty fast to the point where it would tell me I have 30 miles to go to my current steerpoint even though I was right above it (I was attacking ground targets there for about 10 minutes with no hard manoeuvres). Also later my VVI stopped working altogether. So it's pretty buggy at the moment.
Having played with "lower simulation update rate" for 2 days, I would advise to not activate this option. The INS degrades pretty fast to the point where it would tell me I have 30 miles to go to my current steerpoint even though I was right above it (I was attacking ground targets there for about 10 minutes with no hard manoeuvres). Also later my VVI stopped working altogether. So it's pretty buggy at the moment.