Those are "workstations" not the lowest cost "desktops", quit trying to change the argument just so you can finally accuse others of being the liar.
http://configure.us.dell.com/dellstore/config.aspx?c=us&cs=19&l=en&oc=DE51F2&s=dhs&fb=1
Desktop with the same processor, memory that can be moved up to 512 (same as the 'workstation'), Bigger Hard Drive, and other equivalent equipment. Why is this a desktop and the Linux box a 'workstation'? With the same internal components is the difference just the Operating system? Its sad to see you try to use semantics because you are caught lying if not in word, in spirit..