For iMac 27" A1312 Mid 2009 2010 2011 upgrade NVIDIA GTX 780M 4GB Video Card | eBay
iMac mid 2011 GPU upgrade | MacRumors Forums
Sunvalley 2GB Graphics Video Card Replacement for Apple iMac Mid-2011 27 Inch A1312 Core i7 3.4 MD063LL/A MD063 Desktop PC Computer, ATI Radeon HD 6970 GDDR5 2 GB, New GPU Upgrade Repair Parts : Electronics - Amazon.com
Need to repair this iMac 27" 2011, Please any suggestions? GPU Temperature is not even 50 C : r/mac