Mushkin 996625 Ascent Series 4GB 2x2GB PC3-12800 DDR3 1600 CAS 7-7-7-6-18 Timings 1.85-1.95V Memory (Black) 4 GB Dual Kit (2 X 2 GB) DDR-1600 (PC-12800) DDR3 240-PIN DIMM 1.85V - 1.95V 7-7-6-18