I had the AMD Radeon HD 6970 replaced in my mid 2011 27 inch iMac at the local Apple Store. The display went to gray with narrow vertical black bars. They could not duplicate the problem but replaced the card anyway under their recall program. I had to wait a few extra days as they did not have the 2 Gb version in local stock. The screen colors now seem more vibrant. In hardware overview the only difference I see is ROM Revision went from 113-C2960K-152 to 113-C2960K-205 EFI Driver Version 01.00.507 to 01.00.577 Did have a problem unrelated to the graphics card when I got home. I could not connect to my wireless network. I had to haul it back to the Apple Store. A connector did not get seated properly when the iMac was reassembled. Anyone who qualifies under this recall, I would recommend getting the graphics card replaced. As I recall, you are covered for replacement up to three years after purchase date. After that you are on your own. It would have cost me shy of $300 if I had missed the deadline.