8GB KIT (4 x 2GB) for HP-Compaq Workstation Series xw6400 xw6600 xw8400. DIMM DDR2 ECC Fully Buffered PC2-5300F 667MHz Server Ram Memory. Genuine A-Tech Brand. at Amazon.com
Solved: where RAM SIMM Slots for HP xw6600 Workstation Product Speci... - HP Support Community - 7500509
Desktop, HP Xw6400 Workstation, 2x Intel Xeon, 4GB RAM, DVD-RW, Win XP Sticker (Verification Req.), No HDD, No VGA/Power /Keyboard/Mouse Cables, Unit Powers On, No Display, Sold As Is, Salvage. [94972+69]
8GB Kit 2 X 4GB DDR2 Server Memory Upgrade for HP Workstation XW6400 SDRAM ECC Fully Buffered FB DIMM PC2-5300 240 pin 667MHz RAM (PARTS-QUICK Brand)
CMS 16GB (4X4GB) DDR2 5300 667MHZ ECC Fully BUFFERED DIMM Memory Ram Upgrade Compatible with HP/Compaq® Workstation Xw6400 Ddr2 Pc5300 Fully Buff for Server Only - B104 at Amazon.com
XW6400 Workstation - RAM upgrade help - HP Support Community - 5742087