How to Upgrade/Replace GPU Graphics Card on Mid-2011 21.5" iMac - YouTube
iMac – Wikipedia
Apple 27" 2009 iMac 4GB Graphics Card - replace Radeon 4850 part number 661-5315 | eBay
Amazon.com: Original 2GB Graphics Video Card Upgrade Replacement for Apple iMac Mid-2011 27 Inch A1312 Core i7 3.4 MD063LL/A MD063 Desktop PC Computer, AMD ATI Radeon HD 6970 Spare Parts Full Tested :
iMac 2009 to 2011 (A1311/A1312) Upgrade Guide – MacintoshMen
Apple opens graphics card replacement program for some mid-2011 iMacs - 9to5Mac
Further Explained: Apple's iMac 2011 Model Hard Drive 'Restrictions'
How to upgrade a Mac: Swap in new RAM, graphics card, hard drive and more | Macworld
Someone gave me this unwanted Mac, anyone know if you can upgrade the graphics cards on these ? Keep seeing conflicting information it's a 24" early 2009 imac : r/mac
Original Ati HD 6970M 5750m 4850 4670 Grafikkarte Video Karte 1GB 2GB 109-C29657-10 Für Apple iMac 27 "A1312 GPU 2009 2010 2011 - AliExpress
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