Product Detail Module Size - 4GB kit (2GBx2) Package - 240-pin DIMM Feature - DDR3 PC3-8500 Specs - DDR3 PC3-8500, CL=7, Unbuffered, ECC, DDR3-1066, 1.5V, 256Meg x 72 . The "Crucial Technology CT2CP25672BA1067 4 GB 2 GBx2 240-pin DIMM DDR3 PC3-8500 CL=7 Unbuffered ECC DDR3-1066 1.5V 256Meg x 72 Memory Kit" is best product for you. We recommended Crucial Technology CT2CP25672BA1067 4 GB 2 GBx2 240-pin DIMM DDR3 PC3-8500 CL=7 Unbuffered ECC DDR3-1066 1.5V 256Meg x 72 Memory Kit