2GB ECC RAM Memory Upgrade for the HP Workstation xw4400 Desktop System (DDR2-667, PC2-5300) Guaranteed Compatible for the HP Workstation xw4400 Desktop System. Please note this is an ECC module! The HP Workstation xw4400 can use both ECC and non-ECC memory, but often the two will not work together. If you want to keep your current memory and use this memory with it, verify you have ECC in the system before ordering! Need help? Give us a call at the toll-free number below. Speed up your system with up to 8.0GB 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!