For iMac 27" A1312 Mid 2009 2010 2011 upgrade NVIDIA K3100M 4GB GPU Video Card | eBay
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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 :
For iMac 27" A1312 Mid 2009 2010 2011 upgrade NVIDIA K3100M 4GB GPU Video Card | eBay
Where is the GPU located and what gpu is it? (Late 2009 21.5” ) : r/mac
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Original Ati HD 6970M 5750m 4850 4670 Graphics Card Video Card 1GB 2GB 109-C29657-10 For Apple iMac 27" A1312 GPU 2009 2010 2011 - AliExpress
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