APPLE IMAC 2011 A1312 AMD HD 6970M - Graphics Card with NEW 6970M GPU & 1 GB RAM £399.99 - PicClick UK
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
Apple opens graphics card replacement program for some mid-2011 iMacs - 9to5Mac
Original Graphics Video Card GPU Replacement for Apple iMac A1311 Mid-2011 Core i5 2.7 MC812LL/A MC812 21.5 Inch Desktop Computer, AMD Radeon HD 6770M GDDR5 512MB Repair Parts : Electronics