GPU ATI 216-0811000 Graphic Video IC Chip for iMac 27" A1312 (Mid 2011)
Hotechon Modded Big 3 Pipe Gpu Heatsink For Imac 27" Late 2009 To Mid 2011 Graphics Upgrade - Laptop Lcd Screen - AliExpress
Apple Initiates Video Card Replacement Program for Radeon HD 6970M Equipped Mid-2011 27” iMacs
Big Sur on iMac 27", Mid 2011, flashed 4GB NVIDIA Quadro K4100M by Nikey22, having issues with screen brightness, any ideas? Brightness control was working with Catalina Patcher, after installing Big Sur
Upgrading the graphics in our 2011 iMac (first attempt) - YouTube
Upgrading an iMac GPU for METAL Support! Late 2009 – Mid 2011 Models - YouTube
Apple opens graphics card replacement program for some mid-2011 iMacs - 9to5Mac