Artifacts reboot - video card or power supply?

Vidyakh ~ 2 years old (3060ti msi gaming x trio), artifacts recently got out, the computer got up for ~ 5-10 seconds, black screen - reboot. This happens at a random time, once every 1-7 days, no matter if I play a hard game or watch a video on YouTube. Sometimes artifacts appear, a black screen for a couple of seconds, a shutdown sound (like the USB was pulled out) and everything appears back to work normally. It happened after the artifacts when the game was started, it wrote - an error, perhaps a problem in the video or firewood (I don’t remember verbatim). There is a chance that the problem is in the bp (Corsair sv650) he is 4-5 years old? 12 volt line sags until 11.31. Artifacts do not depend on the load, drove stress for 5-20 minutes, the temperature is normal, just at a random moment, it happens a couple of times a day, it happens once a week.