So I've been running into two issues recently after adding a custom water cooling loop, RTX 2080 Super Founders card, and ASUS Prime X470-Pro mobo to my PC (other hardware includes Ryzen 3800X, 32gb 3200Mhz RAM, SuperNova NEX750B PSU).

After adding the cooling loop and GPU, I noticed two issues which may or may not be related. First, when I hit the power, it starts for 2 seconds, the power cuts, it auto starts and then fully boots. So it false-starts and then boots.

The bigger issue, however, is when I play a game (the one I noticed it in was the new Modern Warfare) after a few minutes, the computer hard crashes. No BSOD, just from full on to full off.

Now I got to thinking it may be a bad or just old PSU, as I've used this one for years. I used my PSU tester on it, which shows numbers almost up to the exact voltage, but nothing a full volt low. I did, however, read that one solution which may mean PSU is to reduce GPU power. I did so to 80% and it works fine.

So I just want a second opinion, as I'm already exceeding my budget thus far, to ensure that it definitely is the PSU before I go looking to upgrade that. Anyone have any similar issues, experiences, or know what might be going on?