Amazon.com: Valley Of The Sun 2GB Graphics Video Card Upgrade for Apple iMac Mid-2011 27 Inch Core i5 MC814LL/A MC814 A1312 Desktop All-in-One PC, AMD Mobility Radeon HD 6970M Replacement Repair Parts :
SOLVED: What GPU's are compatible with iMac 27" 2011? - iMac Intel 27" EMC 2429 - iFixit
SOLVED: What GPU's are compatible with iMac 27" 2011? - iMac Intel 27" EMC 2429 - iFixit
For iMac 27" A1312 Mid 2009 2010 2011 upgrade NVIDIA GTX 880M 8GB Video Card | eBay
Amazon.com: 2GB Graphics Card GPU Upgrade Replacement for iMac 27 Inch Mid- 2011 A1312 Desktop Computer Core i5 3.1 MC814LL/A MC814, AMD Radeon HD 6970M GDDR5 2 GB MXM Video Board Repair Parts :
For iMac 27" A1312 Mid 2009 2010 2011 upgrade NVIDIA GTX 780M 4GB Video Card | eBay
Cracking Open the 27" Apple iMac (2011) | TechRepublic
Today picked up a $20 2011 iMac 27” with working gpu too! : r/mac
iMac 2009 to 2011 (A1311/A1312) Upgrade Guide – MacintoshMen