Apple IMAC 27” A1312 Nvidia Quadro K5100M 8GB MXM Video Card GPU Replace 6970M | eBay
iMac Intel 27" EMC 2429 Radeon HD 6770M Graphics Card
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, MXM VGA Board Repair
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
iMac Graphics Cards | iFixit
Graphics Video Card GPU Replacement for Apple iMac Mid-2010 A1311 Core i3 3.06 MC508LL/A MC508 21.5 Inch Desktop Computer, ATI Radeon HD 4670 GDDR3 256MB, MXM VGA Board Repair Parts : Amazon.co.uk:
iMac 27 How to save money | Imac 27 Graphics card replacement | How to fix graphics card at Home - YouTube