Chris, Dean Dauger (from UCLA) is "the man" when it comes to multi-processor, parellel and cluster-node set-ups for Mac OS 9 & 10. He has been able to achive 6 GFlops/sec on a cluster of four PPC G4s (whatever that means). He's really into Quantum Mechanics & Computers in Physics, real "Treck" stuff. He has a couple applications to help set this up and has info on codeing for MP systems at his sites: http://www.dauger.com/ http://exodus.physics.ucla.edu/appleseed/appleseed.html OSX will help with mp but the application really needs to be written properly to take real advantage of it. He has info on that also if you are into codeing. (Get that "Atom in a Box" while there, it's really interesting)