Setup: PC running fine on UPS when powered on. GPU/CPU stress test finds nothing wrong. All temps are ok (below 50; gpu: 70) except SYSTIN temp which is 130+ (seems like a broken sensor).
Whenever power goes out, the UPS switches to backup power: GPU driver crashes.
If the PC is restarted while on UPS backup and GPU/CPU tress test are run, nothing is wrong including no driver crash.
Putting power back on to UPS: everything OK.
Plugging the UPS out from main: driver crash.
What could be the reason and solution?