Originally Posted by Nephyrin
This does look a *lot* like a defective card - especially the corruption at the bios phase. It might be worth moving the card to another system to rule out other causes, but if its happening on multiple installs with different drivers, and in the bios, I would personally guess that the hardware has indeed died
Sadly, your guess was absolutely correct. My gpu is toast. After replacing it with another one, everything is back to normal :-) ...