Computer randomly reboots during games. What could be the cause?

[xghoststrike]

I have a fairly high-end PC that i have had for about 1.5 years now, practically every part was bought brand new around the release date of the 1080ti so my hardware isn't super outdated or anything. I would say after about a year of owning the pc was when I first experienced my random shutdown. I can't remember what game it was that i as playing but it just turned off and then back on shortly like a reset button from the case. it happened again around 6 months later and I thought it was cause of power shortage so I got a UPS. I never experienced it again up until about 2 months ago. I got fallout 4 and the game would cause my PC to restart about every 15 mins and even sometimes just from starting the game. I learned it was because my settings were too high in fallout so i turned them down a fair amount and i never experience the restart again. I started play Elder Scrolls Online with a friend and the restarts are happening again. I again turned the settings down a fair amount but they are still happening, not as much but still so. In Fallout 4 it would happen anywhere anytime, in ESO it seems to happen around hectic heavy fighting times but it also happens in lame simple times too.

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Would anyone have an idea on what the issue might be? It is most definitely not a heating issue, my temps are exemplary, nor is it my ram or storage. I have also ran GPU and CPU stress test for a while and my pc never restarted. so PSU or MOBO?

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I also recently did a full restore and installed a new version of windows on a new SSD so even my boot drive is different.

 

[ikaz]

That could point to failing Power supply what model and wattage ?