Patriot Viper 3 Series, Black Mamba, DDR3 8GB (2 x 4GB) 1600MHz Dual Channel Kit (PV38G160C9K) at Amazon.com
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
Kingston Value (KVR16N11S8/4) RAM 4GB 1600MHz PC3-12800 DDR3 Non-ECC CL11 DIMM SR x8 Desktop Memory at Amazon.com