After spending at least an hour swapping memory chips left and right I realized that I do have a card which uses the same memory and is known good. Well long story short it's not the memory. Swapped the memory in from the know good card and it's still artifacting, swapped it back and the other card is still working perfectly. I will test the other memory chips in this card at a late date just to be sure though.
I did learn a lot about the card though.
- It needs at least 6 memory chips to produce its normal picture
- It needs at least 2 to work at all
- If you go down to one you have to go up to three again to make it work again
The new picture is with the known good memory chips, so some new artifacts have joined the party.
I also noticed testing in EDIT for artifacts (cause the don't show up as often with just 2 memory chips) that scrolling the screen with enter seems to clear the artifacts and only produce an artifact once in a while, while scrolling with the cursor keys produces a whole rainfall of artifacts (at least that is what it looks like since the artifacts just scroll of the screen)
Maybe somebody with knowledge can make any sense of this.