Hey Fusion, have you tried:
Testing them individually;
Cleaning them for dust bunnies;
Considering that it might be your main PSU causing artifacts;
Different GFX drivers;
A 2080Ti is an overkill for anything less than 4K, imho. I have one. You’d be better off with a good second hand 1080 Ti, you should get a good performance boost over the standard 980.
It’s a pity I’m not over there as I have two spare 980 Ti going.