PSU dieing?

[Profquast]

When overclocked my PC sometimes randomly crashes, not the usual blue screen but everything goes black, the keyboard, mouse, and even power buttons don't work anymore. The weird thing is all the fans keep running. I haven't experienced a crash at stock settings yet, though it throttles heavily and doesn't use more than 57 watts according to HWiNFO64's sensor page. Specs are a FX 8320 on a Gigabyte 970A-UD3P and a XFX PRO Core Edition 550 Watt 80+ bronze PSU. Videocard is a HD 6450 at the moment, my HD 7950 is on it's way back from RMA because it was also throttling but they couldn't replicate the issue so I'm thinking it might be te PSU. I don't have another PSU except for a DELL OEM one to test unfortunatly. Any thoughts?

[ThatAngryGnome]

Try with different voltages. It could be that you're not giving it enough power or you're giving it too much. Either way, your processor won't run. Also, you messed up in the title (dying, nor dieing)

[Profquast]

Oops, English is not my first language and tenses are not really my thing. However it can't keep it stable at 4.0 GHz at 1.4125 Volts and LLC set to Extreme. At stock speeds it underclocks 2-3 cores to 2900 MHz while the rest is at 3500 MHz when testing with prime95.