For iMac 27" A1312 Mid 2009 2010 2011 upgrade NVIDIA K4100M 4GB GPU Video Card | eBay
Video Cards NVIDIA GeForce GPU Content Archive Listing for 2009 - Page 1 | TweakTown
Amazon.com: 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: Original Graphics Card for Apple iMac 2009 Core 2 Duo 3.06 MB420LL/A MB420 A1225 24 Inch All-in-One Desktop PC, NVIDIA GeForce GT 130M GDDR3 512MB, GPU Video Board Replacement 180-10816-0000-C01 :
24" iMac A1225 MB420LL/A early 2009 - Video Card NVIDIA GT130 512 MB 6 - Part Haven