G.Skill RipjawsX 4GB (2 x 2GB) DDR3 PC3-12800 for Sandy Bridge (9-9-9-24) Dual Channel kit (F3-12800CL9D-4GBXL) 4GB DDR3 PC3-12800 Dual channel kit 2x2GB 1600MHz CL9 (9-9-9-24) For Intel Sandy Bridge platform 240 pins 1.5V