Two quad-core Intel Xeon CPUs can be installed in the HP DL380 G6 ('2'), for a maximum of eight cores. It will also work with a single quad-core CPU. Frequencies range from 2.0-2.8GHz. There are nine memory slots either side of the CPUs ('1' and a '3'), which require DDR3 SDRAM. Up to 144GB (18 x 8GB) of registered memory can be installed via the HP DL380 G6's 18 memory slots.