Since I have a dual proc system, I can tell you P4/p5 is not multithreaded. You can always tell because single threaded apps will peak out one processor while not affecting the other. When I render in max it effects both. It's still great having a dual proc system, because while one app is churning on one proc, I can do other things on the other with no noticable system lag (some times it's actually better that apps aren't multithreaded). For most people I recommend a single processor system because it may not be worth the additional expense. -Mark