PNY OPTIMA 512MB DDR 400 MHz PC3200 Desktop DIMM Memory Module MD0512SD1-400 Memory capacity upgrade provides improved system performance and responsiveness Deliver all the productivity your PC has to offer with PNY Memory Compatible with PC3200 (400 MHz), PC2700 (333 MHz), and PC2100 (266 MHz) systems Helps prepare your PC for running Windows Vista Easy installation, Free 24-hour Technical Support, and Lifetime Warranty!