Did some testing last night on the 3090 using my CX tv. Please a good solid 3-4 hours of COD:MW and did not have 1 crash. Boost speeds were around 1950-1980 most of the time.
Really does make me wonder if its a driver issue though. I know if I enable Gsync on the CX tv it will drop its signal.
It's probably a combination of both, cards boosting too high due to lack of testing with drivers/firmware and the cheaper designs having more issues handling it due to the capacitor layout.