HP 16GB 2X 8GB PC2-5300 DDR2-667 2Rx4 ECC Fully Buffered FBDIMM Memory Kit (HP PN# 413015-B21) at Amazon.com
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,