I'd start with a good cleaning, fresh heatsink compound and be sure the fans work like new. After that I'd get more information to the forum such as:
1. Make, model, AGE of the PSU.
2. The Speccy report from https://www.piriform.com/docs/speccy/using-speccy/publishing-a-speccy-profile-to-the-web
3. Since it's game related, the Userbenchmark.com results too.

Look up DDU as we will most likely disable Windows 10 (if that's in play here) Driver Updates, use DDU then install the video driver you knew to work.