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For iMac 27" A1312 Mid 2009 2011 HD6970M upgrade NVIDIA GTX 765M 2GB Video Card | eBay
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: Valley Of The Sun New 2GB Graphics Video Card Upgrade for Apple iMac Mid-2011 27 Inch Core i5 MC814LL/A MC814 A1312 Desktop All-in-One PC, AMD Mobility Radeon HD 6970M Replacement :