8GB KIT 4 x 2GB HP-Compaq Workstation Series xw4300 xw4300/CT xw4400 xw4600 xw4600/CT DIMM DDR2 ECC Unbuffered PC2-6400 800MHz RAM Memory Genuine A-Tech Brand 8GB KIT (4 x 2GB) DIMM DDR2 ECC Unbuffered 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)