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4GB DDR3-1600MHz PC3-12800 240-pin 1.5V 1Rx8 Non-ECC Unbuffered Desktop Memory by NEMIX RAM at Amazon.com
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