Hey guys, so I've had the 3090 FE basically since launch and its been doing fine in my system with the Corsair AX860. However, I have been doing mostly machine learning tasks with the card, such as training neural networks and barely any gaming until now. I have the nvidia 12 pin connector which splits to dual 8pins that go to the PSU so the card is sufficiently powered. I don't have any overclock or voltage adjustment on the board, everything is basically stock.
 
I just started playing Red Dead Redemption 2 and I got the latest game ready drivers, latest motherboard and FE bios to enable resizable bar. But what I notice is that if I turn off vsync the card is pushing way more frames and processing a lot more which relates to very large power draw, I can see it shoot up to 300+ watts in the nvidia performance overlay and eventually when it gets high enough my system just reboots itself. If I re-enable vsync in-game, the wattage stays around 140 - 280 watts and I can play without any reboots.
 
My immediate guess is the power supply just isn't good enough for the card to operate at peak. Should I just upgrade the PSU? I'm looking into getting a Seasonic PRIME TX-1000 will that be sufficient? or do you recommend something else? Full system specs is my machine listed in mods rigs in my sig.
 
Thanks!

Some of the older Seasonic PSUs have problems handling a sudden transient load and I think yours has the same issue. The behavior that you described does point the problem to the PSU.

Alright guys I just installed the Seasonic PRIME TX-1000, literally got it a few hours ago. And holy smoke! my 3090 FE is stable!!! I'm running a longer benchmark now, but I was able to load FurMark and toggle spacebar between the run to pause it and resume which forces the card to shoot up to 352 watts. This would have rebooted my system on the older PSU. I'm so thrilled! I can finally enjoy the card.  Here's a screenshot attached for anyone interested.