1GB RAM Memory Upgrade for the HP Pavilion a630n, a636n, a656x and a730n Desktop Systems (DDR-400, PC3200) Guaranteed Compatible for the HP Pavilion a630n, a636n, a656x and a730n Desktop Systems Speed up your system with up to 4.0GB of Memory! Lifetime Replacement Warranty! Will ship the same day when ordered at or before 4pm EST! All others ship next day! Fully-staffed call center to help with installation or inquiries! Call 866-335-1355 with questions or for help!