Computer shutting off while playing - is it a PSU issue?

[DrFire]

As the title says, I'm getting issues where after my GPU (R9 290) has been running for a while at higher temps (80C max), my entire computer just hard shuts off like the power was cut off and tries to reboot itself but stops because it's still overheating. I've tested somethings including undervolting my GPU, which actually lets me play for longer, but I still get shut down (and the GPU does get cooler). Given that, I think it's a PSU issue?

The event viewer shows all kernel power events. Oh, also, I can't reboot unless I go to the back of my computer, switch the PSU on/off button to off, unplug the PSU, replug it, and turn it back on. The computer just flat out refuses to turn on if I don't do that after this hard reboot. Heavily thinking it's a PSU problem.

Current build:

i5 3570k OC'd to 4.5 ghz

8 GB DDR3 RAM DDR3

two 22 inch 1080p monitors

240 GB SSD

R9 290

Coolermaster 650W GX 80+ PSU

 

[Quixit]

I'd recommend replacing your power supply, it sounds like it's about to blow. This model has pretty poor reviews, E.G. http://www.hardocp.com/article/2010/11/22/cooler_master_gx_650w_power_supply_review/9#.Vyubcljyvcs so I wouldn't leave it long.

 

[Onus]

Ah yes, the "polished turd in a box" they called it.
In the meantime, back off your overclock. The goal is to reduce power used. Does the PSU get enough air flow through it for cooling? Unless it gets its own air from beneath your case,, make sure it isn't fighting against too many exhaust fans to cool itself; some should be intakes.

 

[DrFire]

I'd recommend replacing your power supply, it sounds like it's about to blow. This model has pretty poor reviews, E.G. http://www.hardocp.com/article/2010/11/22/cooler_master_gx_650w_power_supply_review/9#.Vyubcljyvcs so I wouldn't leave it long.

Well that sucks. Any recommendations for a new PSU? Always open to upgrading as well.