I updated my pc about 2 months ago, before upgrading, I installed the latest bios so the MB support new CPU, default settings, no overclock.
MB (OLD): Asus z370 plus gaming
Cpu and cooler (NEW): i9-9900 (non K) + Dark rock pro 4
PSU (NEW): Deepcool 850-m-v2l
Videocard (NEW): Palit GP 3080
Now sometimes it shuts down, and after ~3 seconds starts by itself (The 'Power ON on power loss' feature in BIOS is disabled). It could happen when I play, or when I watch Youtube or movie with VLC, or do nothing. It is not related to overheating (temps are low) or PSU fail (I tried my old PSU - same). I cleaned and swap RAM modules. It could happen twice a day, or once a month. It shuts down without BSOD, Event Viewer only shows that PC shuts down unexpectedly. It's a nightmare to diagnose this. Any ideas?