Question PC Continues to Shut Off at OS Boot After Installing 2nd New PSU, No Idea What to Do (Sometimes Boots, Unstable)

Jul 26, 2020
Hi, hoping to get some insight on the current strange behavior I'm seeing. I'm currently able to boot into BIOS but essentially just losing power when I tried to boot into Windows. At the time I had thought this was the result of installing a new GPU (2080 Ti) and PSU (SF750). Sometimes I am able to get into windows and it behaves normally for a few minutes before simply dropping power again.

After reinstalling my old PSU (SF600) I found the computer to work fine, so I left it in and continued to use it while waiting for a replacement SF750 to come.

Today I installed the new SF750 and was able to boot into Windows once, but subsequently attempting to results in the same sudden power failure as with the old one.

Am I missing something obvious here? Either both 750's are defective (seems unlikely) or somehow the way my computer is interacting with the higher wattage is resulting in the shutoffs. Additionally, the inconsistency of the behavior makes it very hard to narrow in on what the actual problem is. Any help would be thoroughly appreciated, I really can't figure out what's going on here. Thanks!