I've found a graphics card listed on ebay with graphical artifacts. Not the classic lines or checkerboard patterns but some letters on the bios boot screen are pink shown in the attached picture. This seems a bit odd could this be something other than the gpu.
The pink characters come up very regularly in every line and every 14th and 16th character. This can help narrow down where the issue might be and it can easily be something other than GPU failure.
What graphics card are you having this issue with? That looks to me as if you have a vram chip that's failing.
Fx 5900 xt
What you can try doing is while the computer is on is to push on each ram module. If one of the bga balls has cracked or got damaged then pushing on the chip will make better contact and temporarily fix the issue.
Cheers I'll see if I can get it cheap
