4GB 2X2GB RAM PC2-6400U 800MHZ 2RX8 DDR2 NON-ECC Unbuffered For DESKTOP Memory Brand: Major Brand MPN: HYMP125U64CP8-S6 Type: DDR 2 SDRAM Number of Modules: 2 Capacity per Module: 2 GB Number of Pins: 240 Bus Speed: PC-6400 800MHz Low Density Compatibility: most major brands of desktop DELL, IBM,Compaq, Toshiba, etc. Warranty: 90 Days Replacement