32.0GB OWC Memory Upgrade Kit For 2010-2011 Apple iMac
install - Installing and Upgrading Ram on a mid 2011 iMac (different size RAM) - Ask Different
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HOW TO: Upgrade The RAM to 32GB on a Mid-2011 21.5inch iMac - YouTube
OWC 16GB (2x8GB) ram Upgrade PC3-12800 DDR3L 1600MHz sodimm 204 Pin CL11 Memory Upgrade Kit Compatible with Late iMac, Mac Mini, and MacBook Pro Computer at Amazon.com