Corsair TW3X4G1333C9A XMS3 4GB (2x2GB) DDR3 1333 MHz (PC3 10666) Desktop Memory 1.5V Corsair Memory is optimized for the Microsoft Windows Vista client operating system Latency of 9-9-9-24 for maximum reliability and performance Each memory module is individually tested to give you Peace of Mind that it Will Not Fail, Guaranteed! Industry Leading Lifetime Warranty 2 X 2GB PC3-10666 1333MHz 240-pin DDR2 Timing: 9-9-9-24 1.5v