Original Graphics Video Card for Apple iMac Core i7 2.8 27-Inch Late 2009 A1412 MC507LL/A MC507 Desktop Computer, AMD ATI Mobility Radeon HD 4850 GDDR3 512MB 109-B91157-00, GPU Upgrade Replacement : Electronics - Amazon.com
Upgrade iMac 27" late 2009 video card? - Apple Community
For iMac 27" A1312 Mid 2009 2010 2011 upgrade NVIDIA K4100M 4GB GPU Video Card | eBay