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ATI AMD 216-0729051 GPU Video Card Chipset for iMac 21.5" A1311 (Mid 2011- Late 2011)
iMac (Model No:A1311, current OS) does this when I try to boot it up, then goes to a white screen. Graphics card failure? : r/applehelp
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2010 iMac GPU Upgrade to NVIDIA GTX 765M - YouTube
Apple iMac 21.5" A1311 Graphics Card Mid 2011 ATI Radeon HD6750M 512MB 631-2052 | eBay
Amazon.com: 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 Board Repair Parts : Electronics