Funky artifacts including jagged black triangles on screen
sounds like VRAM that's unstable (too low voltage, too high clock, too tight timings, etc)
I bet if rip the plate off it says Hynix on those chips.

gpu-z is reporting Samsung RAM but it must use a bit of Hynix for something.
OMG stay away from MSI and cards with Hynix RAM or you'll end up so butt-hurt your asshole will drag on the ground behind you as you walk.