||4 (2 banks of 2) Install in pairs
||1) Except for a single DIMM in the first slot, all memory must be installed in matched pairs. Three DIMM configurations are not supported.
2) The 4 & 8GB upgrades require BIOS version R1B0S4 or later. With 4x2GB DIMMS memory speed automatically decreases to DDR333. Using the DRS2100Z/8GB upgrade automatically decreases the speed to DDR266.