Question Random black screen while using PC, computer is still on. GPU/PSU?

[Derelictson]

Hello, my PC worked completely fine until a couple of days ago. I would randomly get black screens and no signal to my monitor. The PC would still be on, and I was able to still talk to my friends on discord while the screen was black. The only way to "fix" it was to force reboot it, but even though the PC would act as normal after I did that, it wouldn't take long before I had a new black screen problem.

I feel like I've tried it all. I've done a clean reinstall of Windows and I have also deleted and reinstalled graphics driver with DDU. Sometimes when the black screen occurs I observe that my GPU is losing power because the RGB lights and fans turn off, but that doesn't happen every time. The RBG lights on the GPU also starts blinking a darker red color than the usual orange color that it has. My GPU is about 5 years old now, but my PSU is only about two years old, but I'm unsure of who the culprit is, but I think it's either of those.

I'm thinking of maybe buying a new PSU and try that out, because that will be my cheapest option, but I'm curious to hear what you guys think. Maybe you think my PSU sounds fine and that I should just get a new GPU right away. Or maybe it's fixable without buying any new components?

My specs:
CPU: i7-8700K CPU 3.70GHz, 3696 Mhz, 6 cores
Mobo: ASUS Prime Z370-P
GPU: ASUS GeForce GTX 1080 Rog Strix Gaming
RAM: Ballistix Sport LT DDR4 16GB 2x8GB
PSU: Corsair RM850X V2 850W

 

[DRagor]

Very doubtful 2 years old RMx could be going bad. Plus the symptoms don't point towards PSU. Since PC is still running it is either software problem or GPU is dying. Check Reliability History for any errors that happen when you get black screens.

 

[Derelictson]

Very doubtful 2 years old RMx could be going bad. Plus the symptoms don't point towards PSU. Since PC is still running it is either software problem or GPU is dying. Check Reliability History for any errors that happen when you get black screens.

When I check Reliability History nothing out of the ordinary pops up, only the times when I have to forcefully reboot the PC with the power button. I’ve also plugged the HDMI directly into the mobo and it seems quite stable, no black screens. It might be the GPU that’s dying. It’s working perfectly for a random amount of time before the black screen occurs, I thought that maybe the GPU would not be working at all if it was broken, instead of randomly working and giving black screens, but I’m no expert at all

 

[DRagor]

I thought that maybe the GPU would not be working at all if it was broken, instead of randomly working and giving black screens

There are many ways GPU can fail. Had one that would crash only when running 3D games otherwise it worked fine. Random black screens is actually quite common way to fail.
The final test would be to put your GPU into another PC, if it behaves same way then its 99% probability for failed GPU.