Computer Instantly Black-Screening

[MegaShadders]

Hey, I've had this repetitive issue with my pc, and it's been going on for a while. When I'm in high 'intensity' gaming my pc just instantly shuts down, no shut down screen just black. There's no signal to the monitors so I've always had the mentality that this was a graphics card issue, I had a 780 for a while, while this was happening so I thought it was just old, and time to get a new one, and when i lowered the quality it stopped. Once I got my Asus 980ti strix I thought the problem was gone, but after maybe 3 or 4 weeks, it's started to do it again, and a lot. This makes me think it's something else, or something damaging the GPU god forbid.

 

Here are my specs:

CPU: AMD-9590 (Don't ask, I know it was a poor choice, I was pretty clueless when I brought it)

Motherboard: ASRock 990FX Extreme9

GPU: ASUS 980ti Strix

PSU: 750W ATX 12V Model: 750UB

2 1080p Monitors 60hz dvi-single link(for some reason)

Nothing overclocked

 

Now you probably would guess it's the terrible temperatures and power consumption of the CPU, and that makes sense, lets be honest.

This is what CPUID Hardware Monitor read just before the blackout

As you can see from this image, the temperatures aren't high neither is the power (compared to the 230W it's advertised at)

For the GPU it just puts power in percentage which is confusing so just half the power rating of the GPU, (I can't seem to find the value so if anyone knows I'll edit)

Now the PSU is old, so it might be faulty and that's my biggest lead right now.

 

Here's a weird thing though and it's leaving me confused, when it blacks out, I still hear fans spinning, and lights are still on, even on the graphics card, I doubt the graphics card is taking up around 600W, (unless stuff like a HDD and a SSD take more power than i think) but could it still be the PSU? and just the fact that it's old? And most importantly could it be damaging anything?

 

Another thing I just realised  but the drive temperature on Hardware Monitor is reading 100 degrees C for my SSD, which is running the OS and the games I play, another lead, maybe but surely that can't be right?

 

It mostly happens in Guild Wars 2, good enough graphics and lots of people which put heavy load on and it did put 99% on the GPU, but it also happens in cs:go, less frequently but has happened , it all started to happen when I turned on all 8 cores of my 9590, but I seem to remember the problem occurring after I set it back to 4 cores as well when playing Witcher 3, could this of maybe overwhelmed the PSU and caused damage. In my mind it could be anything so anything you suggest will be great.

[PlayStation 2]

Probably the motherboard, which can't handle it. Underclock it to like 3.5GHz and see.

If you can take the side panel off, tell us the PSU.

[TheRandomness]

Probably the motherboard, which can't handle it. Underclock it to like 3.5GHz and see.

Motherboard has 12+2 phases. I'm pretty sure it's not the motherboard. Or maybe he got some crappy VRMs.

[PlayStation 2]

Motherboard has 12+2 phases. I'm pretty sure it's not the motherboard. Or maybe he got some crappy VRMs.

still dont kill to check

[MegaShadders]

PSU is ATX 12v 750UB, at least that's what it says