For iMac 27" A1312 Mid 2009 2010 2011 upgrade NVIDIA K3100M 4GB GPU Video Card | eBay
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Nvidia K1100M upgrade on the Mid-2010 iMac 21.5' - YouTube
Apple opens graphics card replacement program for some mid-2011 iMacs - 9to5Mac
Amazon.com: Valley Of The Sun 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
How to Upgrade/Replace GPU Graphics Card on Mid-2011 21.5" iMac - YouTube
iMac Mid 2010 21.5" Upgrade Kit - Real Mac Mods
Amazon.com: Original Graphics Video Card Replacement for Apple iMac Core i3 3.2 Mid-2010 21.5 Inch Desktop Computer A1311 MC509LL/A MC509, AMD ATI Radeon HD 5670 GDDR3 512MB, GPU Board Repair Parts : Electronics
Original For iMac 21.5" A1311 27" A1312 K610M GDDR5 1GB Upgrade Graphic Video Card GPU N15M-Q2-B-A1 For HP ZBook 15 - AliExpress
2010 iMac GPU Upgrade to NVIDIA GTX 765M - YouTube