The IMac GPU Becomes Upgradeable, With PCIe | Hackaday
2011 iMac GPU Upgrade Now with Brightness and Boot menu - Absolutely Worth It! - YouTube
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 GDDR5 512MB MXM Board :
For Imac 27" A1312 Mid 2011 Nvidia Gtx 880m 8gb Gddr5 N15e-gx-a2 Gpu Graphics Video Card For Dell Alienware M17x R4 R5 M18x R2 - Laptop Repair Components - AliExpress
Amazon.com: Valley Of The Sun New 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 :
iMac 2011 GPU upgrade to NVIDIA 770M with new VBIOS - YouTube
CUSTOM 27" IMAC mid 2011 with i5 3.1Ghz, 16GB ram, GPU upgrade, MacOS Ventura $500.00 - PicClick AU
SOLVED: What GPU's are compatible with iMac 27" 2011? - iMac Intel 27" EMC 2429 - iFixit