HP Workstation z400 - CMT - Xeon W3680 3.33 GHz - 6 GB - 320 GB overview and full product specs on CNET. Memory Specification Compliance. HP Workstation z400 - CMT - Xeon W3550 3.06 GHz - 6 GB - 500 GB overview and full product specs on CNET. Memory Speed 1333 MHz.