Kingston Technology 8GB (2 x 4GB) DDR2-667 PC2-5300 ECC Registered Server Memory (KTH-XW9400K2/8G) 2 x 4GB Modules for a total of 8GB's DDR2-667 PC2-5300 ECC Registered CL 5, 1.8 Volt Server Memory - This will not work in standard Desktop machines.