Computer shuts off under stress, 4 months into the problem with no clue what's happening

[Deflargo]

I've tried everything. More airflow, lifted off ground, plugging directly into wall, plugging into a different outlet, new power cable, higher fan curve, memtest, checking all cables, cleaning dust, even sending it back to the person I bought it from to diagnose the issue. Nothing seems to show it's overheating (GPU maxing at 85C on Furmark, everything else in 30s), yet it acts as if it is. Doing anything high-stress makes it shut off entirely, as if I unplugged it, and then turn back on. It happens to pretty much every game I try to run (even CS:GO would do it, that's the first time it happened) so I doubt it's software related. Please help me fix this, it's getting unbelievably frustrating.

Specs:
GPU: GTX 1080 FE
CPU: Intel Core i7-7700K
MoBo: ASRock B250M Pro4 SATA 6Gb USB 3.0
RAM: 16GB DDR4 G.Skill Ripjaws (one stick)
HDD: Some Seagate 1TB drive
PSU: EVGA 600W 80 Plus
Cooling: 1 intake fan on front panel, 1 exhaust fan on back panel, some Corsair closed loop CPU liquid cooler

 

[J_E_D_70]

Sounds very much like a PSU issue - those cause hard power offs mainly. It could be the gpu but that’s less likely.

Heat problems cause throttling in most all cases (not power off).

 

[Deflargo]

Sounds very much like a PSU issue - those cause hard power offs mainly. It could be the gpu but that’s less likely.

Heat problems cause throttling in most all cases (not power off).

Anything specific possibly? It really doesn't seem like the PSU is overheating, and the person I sent it in to somehow couldn't replicate it, even when it was under high stress.

 

[rolli59]

You can run Furmark but not games?

 

[Deflargo]

You can run Furmark but not games?

No, Furmark will cause it to shut down too.

 

[J_E_D_70]

If it’s plugged into an UPS, try going straight to wall. If already at the wall, Move to a different room and try.

Odd that it cant be replicated outside your house.

 

[rolli59]

I am guessing the PSU is EVGA B series which is their budget line and suggest upgrading to a higher quality unit in process of elimination.

 

[gamerk316]

If the issue can't be replicated outside your house, it's possible the input power going into the PC isn't clean, causing instability as power draw ramps up. Otherwise I'd blame the PSU.