4GB KIT (2 x 2GB) For HP-Compaq Workstation Series xw8600. DIMM DDR2 ECC Fully Buffered PC2-6400 800MHz RAM Memory. Genuine A-Tech Brand. 4GB KIT (2 x 2GB) DIMM DDR2 ECC Fully Buffered PC2-6400 800MHz RAM Memory Genuine A-Tech Memory Lifetime Warranty Toll Free Technical Support 1-866-557-4527 Designed For HP-Compaq Workstation Series. (See Compatibility List Below)