How to Upgrade/Replace GPU Graphics Card on Mid-2011 21.5" iMac - YouTube
Upgrading the graphics in our 2011 iMac (first attempt) - YouTube
Amazon.com: 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
Upgrading an iMac GPU for METAL Support! Late 2009 – Mid 2011 Models - YouTube
Upgrade 24” iMac video card - ATI Radeon 256MB to NVIDIA GeForce 512MB - Ask Different
iMac 2009 to 2011 (A1311/A1312) Upgrade Guide – MacintoshMen
Amazon.com: 2 GB Graphics Video Card GPU Upgrade Replacement for Apple iMac Mid-2011 A1312 27 Inch Core i7 3.4 i5 3.1 Desktop Computer, New AMD Radeon HD 6970M HD6970M 2GB MXM Board
SOLVED: What GPU's are compatible with iMac 27" 2011? - iMac Intel 27" EMC 2429 - iFixit
hardware - Is it possible to replace the GPU in this 2006 iMac? - Ask Different
iMac 2009 / 2010 / 2011 GPU upgrade — Fixing LED/LCD PWM brightness with an ESP32 | by Fixing Things | Medium