Hopefully you do not encounter the same issue as me, I recently got a PCS computer including the RTX 3090 (Zotac Trinity). A lot of my games crashed, within 10 minutes to an hour.
I've isolated it to the Nvidia driver, specifically with the audio. If you get a similar problem, do a reinstall via Geforce Experience (selecting a clean installation) and take off the HD audio. May save you a lot of time troubleshooting. The audio still works via DP or HDMI. It may differ if you get a different version of the RTX 3090. Anyway, enjoy
I've isolated it to the Nvidia driver, specifically with the audio. If you get a similar problem, do a reinstall via Geforce Experience (selecting a clean installation) and take off the HD audio. May save you a lot of time troubleshooting. The audio still works via DP or HDMI. It may differ if you get a different version of the RTX 3090. Anyway, enjoy