4GBs RAM. ○. The following document for the HP xw includes additional guidelines to configure your system. . XW Dual Quad Core Ghz is the only model supported. ○. (alternative slot – when Slot-5 has IEEE adapter). Slot orders are labeled from top (starting with the monitor card) to bottom. · Configuration using only HP xw · Configuration using HP xw Slot 5 Mhz PCI-X slot must be de-rated to Mhz operation in BIOS config.