Amazon.com: 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
Hotechon Modded Big 3 Pipe Gpu Heatsink For Imac 27" Late 2009 To Mid 2011 Graphics Upgrade - Laptop Lcd Screen - AliExpress
2011 iMac GPU Upgrade Now with Brightness and Boot menu - Absolutely Worth It! - YouTube
Apple opens graphics card replacement program for some mid-2011 iMacs - 9to5Mac
iMac 2009 / 2010 / 2011 GPU upgrade — Fixing LED/LCD PWM brightness with an ESP32 | by Fixing Things | Medium