Question PC turns off while gaming - even with better PSU and regular temps?

[Tymon123]

Hello,

I have this problem when my PC randomly turns off after few minutes of gaming, no blue screen, the screen goes dark and 2-3 seconds later all the fans die. It's kinda worrying because I used to play the same game with the same config few months back and there were no problems.

My current config:
CPU: AMD Phenom II X4 955
CPU cooling: box
MB: MSI 870-G45
GPU: RX 570 4GB
RAM: 8GB RAM
PSU: 550W
Storage: HDD (no SDD)


Steps taken so far:

1. Replaced PSU - even though my old PSU had only 450W, several calculators still gave it roughly 60-80W of reserve. I swapped it for a 550W, but the problem still persists.
2. Checked the temperatures - under stress GPU is 80-85C and CPU is ~50C. While higher than in idle (~30-40C), I'd still consider both temperatures as regular or typical.
3. Run Windows RAM diagnostics - no issues found.

My next step would be replacing CPU's cooling, though I am not convinced about it and though I would ask for an advice first. Thanks for any hints!