PC shuts down after a few minutes of playing

Happened twice now. Complete hard crash, no restart just shuts down. I was monitoring the temps on my GPU and CPU and they were normal right before the shutdown.

This is really bad…what is causing this?
5800x cpu
32gb ram
6900xt gpu

5900x and 3090 here and also has my computer shut off after a few minutes of playing. I had to turn off my power supply before it would turn back on.

Related thread: PC Shutdown during early cut scene

I have a ups, so it triggers the alert that I’m pulling from the batter overloading. I’m able to click to another monitor to quick restore, but as soon as I click back to the game monitor, it beeps in a few seconds. Obviously I can’t run this off the UPS for long, but at least it’s not hard crashing computer. Perk of a laptop, I guess… desktop here, updated graphics.