Power Outage Or Psu Issue?

Hi. I had an shutdown 4 days ago during launching game. I launched Metro Exodus and after cinematic part pc just shutdown<goes off>. I pressed power button ,rebooted again and its fine again. Also monitor flickered 10 seconds after shutdown

Seasonic TX-850W and Rtx 3090 Gigabyte stock

Also when i cut power for 1 second by turning OFF/ON switch in power cord pc restarting,not shutting down.


Is this possible that was a brief power outage or brownout? I ask because In my room i had laptop on connected to other power cord in this moment, and in eventlogs there was not log about power mode changing to battery. Also router plugged to wall dont turned off, because WIFI was active on laptop ,though.
Is this possible that only pc was affected due to brownout?Pc turns off only.
Or maybe not and psu issue?



Also when i cut power for 1 second by turning OFF/ON switch in power cord pc restarting,not shutting down.

 

It sure suggests a temporary unstable mains event. Not good.

But if no other device in the same building or room demonstrated any power problems, then that would suggest your computer's power supply is failing. Also not good. Sadly, there really is no way to tell what caused the event after the fact.

Is everything working properly now? If so, there is little you can do.

If not, then for sure, first thing I would do is swap in a known good PSU to see what happens.

Note I always recommend every computer be on a good UPS with AVR (automatic voltage regulation). While it is the AVR feature that is most beneficial, backup power during an actual outage is also important.