Amazon.com: Original Graphics Video Card GPU Upgrade Replacement for Apple iMac 21.5 Inch Late 2011 Core i3 3.1 All-in-One Desktop PC MC978LL/A, AMD ATI Mobility Radeon HD 6750M, MXM VGA Board Repair
Cracking Open the 27" Apple iMac (2011) | TechRepublic
Amazon.com: Original Graphics Video Card for Apple iMac 2011 Core i5 2.7 A1312 MC813LL/A MC813 27 Inch Desktop PC Computer AMD Radeon HD 6770M HD6770M GDDR5 512MB 109-C29557-00 Replacement Parts : Electronics
For iMac 27" A1312 Mid 2009 2010 2011 upgrade NVIDIA K4100M 4GB GPU Video Card | eBay
How to Bake a Failing Graphics Processor to Possibly Live Another Day - DreamLight.com