PNY OPTIMA 2GB DDR2 667 MHz PC2-5300 Desktop DIMM Memory Module MD2048SD2-667 Memory capacity upgrade provides improved system performance and responsiveness Deliver all the productivity your PC has to offer with PNY Memory Compatible with PC2-5300 (667 MHz), PC2-4200 (533 MHz), and PC2-3200 (400 MHz) systems Helps prepare your PC for running Windows Vista Easy installation, Free 24-hour Technical Support, and Lifetime Warranty!