Question Computer reboots while playing game

[Kulivoko]

What happens is that I play a game, it does not matter what kind of game. Suddenly sometimes after 5-15 sometimes 45 minutes, the computer restarts. There is no BSOD. There is nothing in the event viewer. There is no crash dump, although I have a setup to create a dump file.

this is my computer specs

This is my os

It only started happening quite recently. I have never had that before. Could it be related to the power supply? As the reboot is instant. There is nothing like dump creation.
Can you please help me narrow down the cause or what steps should I do to understand what is the root cause?
Thank you

 

[bignastyid]

Whats the make and model of the PSU?

 

[Kulivoko]

Evga Supernova 850 G3

 

[Kulivoko]

Whats the make and model of the PSU?

I am in the middle of Passmark Memtest. So far no error found but still require two additional passes to finish this test.

edit: passmark memory test is done. No errors were found.

 

[Kulivoko]

Whats the make and model of the PSU?

I experience exactly the same scenario as discussed here:

https://forums.tomshardware.com/threads/pc-crash-without-bsod-or-crash-dump-file.3528480/

Could you please tell, what is the reason behind such PSU crashes of OS? Is there a way to measure, is it because of voltage output that is beyond some sort of limits and then the PSU goes reboot causing entire pc to shut down and restart? I mean how can I measure that. I would like to see at least some log before going to store for a brand new PSU. Could it be because of cables? Is it good idea to simply switch off cables and put a new PSU in place?