Very likely bad video ram. 🙁
Inside the attatched archive there's a .iso of Video Memory (Stress) Test Clean Environment. Burn it to a disc and use it to test the ram.
You can also get the file here: https://www.majorgeeks.com/files/details/vide … tress_test.html
Run the test multiple times by resetting the machine and booting off the CD again. If the errors always occur at the same point it's 99.9% bad ram. If the errors happen at random adresses it's likely a bad solder joint.
Edit: In theory this problem can be caused by bad capacitors but it's almost never the case. Better indicators for bad caps are random crashes under load. I really wouldn't mess with the caps as long as there's still a chance of returning the card.