The only advantage OSX will have with Bryce & MP systems is that which the OS provides to multi-threaded processes of the OS itself. Bryce is "single-threaded" so the only possible advantage may be with OpenGL screen redraws and other sys stuff. The actual rendering may be a little faster from what I've red but not significant. It may be possible to set-up two client renders on the host machine & render a single-frame movie in the net-render feature. This should take advantage of MP systems in theory. Note, I've gatherd this info from several different forums and am no expert on this subject. It does look interesting though.