Four Intel? Xeon MP Processors at 2.80GHz/2MB Processor, up to 8 supported (populated in groups of 4) with 400MHz FSB and the HP developed F8 Chipset, Hot Plug RAID Memory (Hot Add, Hot Replace, Hot Upgrade), 4096MB addressable protected 133MHz ECC SDRAM Memory (2560MB total) standard, 64GB maixmum (when 2GB DIMMs available) with optional Hot Plug RAID Memory (front access) , Two 1100/800 Watt Hot Plug Redundant Power Supplies Standard, Six open Hot Plug slots (64bit/100MHz PCI-X), 4U rack-optimized modular chassis, Dual, integrated Gigabit NICs