Crucial 4GB kit (2GBx2) DDR3-1066 MT/s (PC3-8500) CL7 Unbuffered ECC 240pin UDIMM - CT2KIT25672BA1067 / CT2CP25672BA1067 Increases system performance Two 2GB Sticks In Kit 1.5V, ECC, Unbuffered Server Memory Easy to install Compatible with some of the following brands: HP Workstations, Proliant Blade Servers, Giga-Byte, Supermicro, some Intel motherboards and many others (Please check Crucials memory selector tool for compatibility with your system before purchase)