Question Is my GPU or PSU at fault?

Capitall

Prominent
Dec 6, 2020
9
0
510
Recently I've replaced my 660Ti with a used RX 570 4GB, and didn't change anything else in the computer, as I thought the PSU I had would be okay for the 570.
The card acts normal, I installed drivers without any issues, idles normally, no artifacts.
However, whenever a harder load is put on the GPU ( I've tried Heaven benchmark and a few GPU-intensive games), the PC crashes to a black screen when the GPU temperature is around ~60°C. No lines over the screen, no flashing, just straight to a black screen. I can then no longer hear any sound, can't use the keyboard or mouse and I have to shut down the PC with the power button.

I've tried:
-Uninstalling the old nvidia drivers with DDU and installing new AMD drivers - didn't work
-Reseating the GPU in my system and trying a different 6 pin cable - didn't work
-Rolling back drivers to an older version - didn't work
-Undervolting the GPU - didn't work (tested it with a lot of different voltages)
-Underclocking the GPU- didn't work

I've been stuck on this for 3 days now and I'm not sure if its my PSU causing the issue or I bought a broken GPU (I think its unlikely because no artifacts or weird glitches) which I hope isn't the case because I've spent my savings on it :'). If anyone has any ideas, please comment below.

Full system specs:
i5 3470
8GB RAM
RX 570 Sapphire 4GB
The PSU is an "Enermax" 500w
 
Enermax makes units ranging from rather poor quality to fairly decent quality. Without knowing which specific unit you have it's impossible to say.

Can you upload a photo of the label on the side of your PSU?

Where did this RX570 come from? Was it used?
 

Capitall

Prominent
Dec 6, 2020
9
0
510
Enermax makes units ranging from rather poor quality to fairly decent quality. Without knowing which specific unit you have it's impossible to say.

Can you upload a photo of the label on the side of your PSU?

Where did this RX570 come from? Was it used?
I'll try to get a pic later today.

Yeah the 570 is used, I bought it locally from a guy in my town. I'm not from a large or developed country so it's pretty hard to get anything tech-related for a decent price.