PC keeps rebooting/restarting when playing games

[al-seraidy]

I don't really think it is the PSU, because I've got two PSU's, one being the gigabyte 620e that I have dedicated to my GPU only, and the other one is a 330W external power brick that's hooked to a power board inside my alienware X51 R2 for all of my other components. I can't really see how an XFX RX 480 GPU is not able to get enough juice from a 620W power supply even if it's a bad PSU, all it has to do is power one single component, the GPU. I've also noticed that when my PC shuts down, the gigabyte PSU is not affected and stays on, does that mean that the problem is most likely not coming from the gigabyte PSU?

 

[Carnaxus]

I've never heard of using separate PSU's in anything other than a server. Can the Gigabyte one provide enough power for the whole computer? If so, try taking the other one out of the loop and see if it helps.