[SOLVED] Intermittent NO POST - Is it the PSU?

[Highly Praised]

So I finally fixed up my PC by putting in a new SSD, and then I leave the case open for a week. It does have plenty of dust in there. To get to the point, I attempted to turn on the computer and it wouldn't post. You'd see the fans turn on and the motherboard LEDs for about 3 seconds, and then it would all shut down. I repeated this cycle for about 10 minutes, I tried stuff like checking the important connections and resetting the CMOS battery, and none of that worked. But after about 10 minutes of cycling, the PC not only POSTED, it successfully booted and worked fine. Then I shut it off, and it went back into the cycle of failing to post. This went on for about another week, I got my XFX PRO 650W approved for RMA, and then I tried to boot the PC, and it worked. So now, the PC mainly works, although it has intermittently failed to POST again, or I think once or twice it reached POST and then shut off. Should I RMA the PSU, or could it be the motherboard? I'm just worried there is a chance that it may not be the PSU/they may not be able to replicate the issue. Thanks for the help in advance guys!

SPECS:

XFX PRO 650W 80 + Bronze
WD Blue SN500 M.2 NVMe SSD
Gigabyte Z97X Gaming 5 Motherboard
i7-4790K - OC'd to 4.5Ghz
Cooler Master Hyper 212 EVO
XFX R9 280 Double D Black Edition - Minor OC

 

[Barty1884]

Far from definitive that it's the PSU.

Have you removed the overclock and run at stock to see if the issue reoccurs?

 

[Highly Praised]

Far from definitive that it's the PSU.

Have you removed the overclock and run at stock to see if the issue reoccurs?

Doesn't resetting the CMOS effectively do this? Or is that only temporary, because I do feel like I checked the BIOS at one point and it was still running at 4.5Ghz.

 

[Barty1884]

It should do that, but manually ensuring you reverted the OC would bea good place to start.

 

[Highly Praised]

It should do that, but manually ensuring you reverted the OC would bea good place to start.

Could it really be the CPU? Or are you leaning towards the idea that the motherboard can no longer handle the extra load that comes from overclocking? The CPU is 2 years old, but the rest of the gear is from 2015.

Anyways, I've attempted another CMOS reset, but even after 10 minutes of cycling, this rig is failing to hit post. Can't access the BIOS as of now, but I'll give it another shot in the morning.

 

[Barty1884]

Without evidence otherwise, I'd always be more inclined to look to the motherboard opposed to the CPU.
CPU's are pretty robust and, other than DOA, they will last for many years under normal conditions.

However, with excessive voltage, or temps etc, that can all change.