4GB 2 X 2GB PC2-5300F 667MHz 240 pin DDR2 SDRAM ECC Fully Buffered FB DIMM Server Low Power Memory for HP Workstation XW8600 (PARTS-QUICK BRAND). Equivalent to HP Part Numbers: 397413-B21, 442823-B21,
Hynix 4GB(1x4GB) DDR2 667MHz PC2-5300F 2Rx4 FBD ECC Server memory 4gb FB-DIMM RAM at Amazon.com