1GB RAM Memory Upgrade for the Compaq Business Desktop d530 CMT and d530 SFF (DDR-400, PC3200) Guaranteed Compatible for the Compaq Business Desktop d530 CMT and d530 SFF 800MHz front-side-bus systems. Please note that the 533MHz and 400MHz Front-side bus systems use lower speed DIMMs. If you are unsure or need help figuring out which you have, feel free to give us a call! 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!