iMac Intel 27" EMC 2374, AMD Radeon HD 4850 Video Card Removal & Repair - iFixit Repair Guide
Amazon.com: 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 : Electronics
Amazon.com: Original 1GB Graphics Card for Apple iMac 2010 27" Core i7 2.93 Desktop Computer MC784LL/A MC784 A1312, ATI Radeon HD 5750 GDDR5 1 GB Video Cards GPU Upgrade Replacement Parts : Electronics
Burn the VGA and Fix your iMac - Don't Pay Shitty Problems!!! - YouTube
Amazon.com: Graphics Video Card GPU Replacement for Apple iMac Mid-2010 A1312 Core i5 3.6 MC510LL/A MC511LL/A 27 Inch 27" Desktop PC Computer, ATI Mobility Radeon HD 5670 GDDR3 512MB Genuine Parts :