[SOLVED] Is my GPU faulty?

[Fajitamunch]

Hello everyone.

During lockdown I got bored and gave myself a project build whereby I built a computer using a mix of used and new parts. I bought a new SSD, new cooler and new 550w PSU.

The rest of the parts were used.

I've had it for 3 weeks now and a couple days ago I occasionally started getting weird artefacts on screen. I'll turn my computer on and it might rarely show up in bios, or it might more commonly go to the rainbow colours where the windows login page would normally be. Half the time it boots up just fine.

I did a small experiment, when it booted up fine, I got 5 clean restarts from it. When I turn the computer off and then on again, the failure rate seemed to be around 50%. Once it's on, it seems to work fine and I can't game for hours without issue. I have no idea what component is causing this to happen, any troubleshooting tips would be much appreciated.

Occasionally I get different types of artefacts too: sometimes a checkerboard of colours. Other times at boot there would be a flashing dash sign in the top left corner while the rest of the screen is covered in weird colours with flashing letters.

4670k
4x4gb DDR3 1866
Sapphire Rx 570 nitro+ 8gb

https://imgur.com/a/cS7GzIr

View: https://imgur.com/a/cS7GzIr

 

[velocityg4]

I'd suspect the GPU. Especially if you try another monitor and cable. Yet get the same response at POST or the monitor and cable have no issues on other computers.