In one of my rigs, I get this problem that Windows get unresposive and slow. Have the error message unable to get fan speed - Unknown Error (999) as somebody reported before.
Tried lowered mem with no sucess and cards seems work in my test PC at 1000+ in mem OC.
Combo of GTX 1660 TI and RTX 2070.
Any ideas? Rig is working fine with other algos.
you will see at which card get fan speed error, go to afterburner that select that particular card, then you should see the clock speed is down in half, that's because you've overclocked it too much, back down a bit and restart your rig then it should be normal again
It is radom which card reports first. Lowered all to 800, still same problem.