Unlike Mach4 using the PP, LinuxCNC/PathPilot using the Mesa board should be relatively un-fussy about the specific motherboard being used. It is the Mach3 PP driver that is primarily responsible for most MB-related problems. When the PP is eliminated, and replaced with a motion controller, even Mach3 can be configured to work well with almost any PC, including most laptops. I would bet the Dell Dimension would work just fine with PathPilot.

Regards,
Ray L.