The processor chips are just part of the story Dave. Servers typically are heavily optimised to be computing race-horses compared to workstation nag that is designed to be an expert in generalisation. But all this means very little ... let Uncle Sabot explain ...
The typical server we use for VMware, the humble
HP ProLiant BL685 C Class Blade has 4 Quad Core Processors (that's 16 processing cores) and 64GB RAM (expandable to 128GB). Typically we'll get 16-30 virtual machines out of this kind of machine. A monster of a machine compared to workstation but all this mean nothing if one, or more, of the virtual servers is working the I/O hard reducing the amount available to others virtual servers, this will happily bring this bad-boy to it's knees.
Not every software activity out there is suitable to work in a virtual machine and funnily enough I wrote a blog post on the subject of
VMware Candidate Selection. I would happily repost it here if it wasn't long but I'm happy to if I get a few yays!
So Turrican go have a look at what your VM's are doing, it's time to get to know
Windows Reliability and Performance Monitor. After all you may want to rethink your strategy of turning you workstattion into a VM hoster. Give me a shout if you need some help.