G.SKILL Ripjaws Series 8GB (2 x 4GB) 240-Pin PC RAM DDR3 1600 (PC3 12800) Desktop Memory Model F3-12800CL9D-8GBRL - Newegg.com
SK Hynix 8GB PC3-12800 Desktop DDR3 1600MHz Non ECC 240Pin DIMM Memory RAM 1x 8G 806998774547 | eBay
OWC 8GB PC3-12800 DDR3L 1600MHz SO-DIMM 204 Pin CL11 Memory Module Upgrade Compatible with iMac, Mac Mini, and MacBook Pro (OWC1600DDR3S8GB) at Amazon.com