Followup on the glitching RX 7900 XTX from a few days ago.
I did as suggested, tried all DP ports. The green glitching remains.
HDMI seems to not have the green glitching, but occasioanlly blackscreens, and sometimes appears to not have signal at all..
The card is not stable at all, system tends to freeze after less than a minute.

With linux the same things happens. Once any kind of graphics driver loads, the card produces a corrupted signal. Please note that I have no clue how to linux.

What makes me think it's VRAM instead of GPU was this: Loading into World of Warships made the glitches disappear. Things were stable for several minutes until I alt-tabbed out of the game.

Anyway. replacement 9070 XT is ordered, roughly the same performance and avoiding the 12VHPW for another few years.
I will look into finding a GPU repair shop. Anybody know one in Germany?