I'm running P5 in a slow old small system (K6-III+ 450 with 256Mb of PC133 ram running at PC100 speed and Win2K Pro. Everything works fairly well, but I have noticed the materials room screen graphics hanging around (and sometimes the Render Options screen) after they should be closed. I have found that, paradoxically, it sometimes helps to LOWER Poser's priority (so the OS can catch up to it), and when it's doing something really intensive like calculating hair and cloth dynamics, just go off and read email in another application or pop in here and read posts. Judy appears to have some scaling problems but those are Judy problems, not P5 (they are the same if you load her in P4) that are absent from Don. And on my slow system I've learned the hard way to pose first and add hair and cloth dynamics last. And I think it will be a while before the power of the materials lab hits home. That's one interesting engine and basically controls the render in much the same way that some of the professional engines do. And that damn bug where the document window keeps decrementing its height after I set it and lock it is annoying (but not fatal). Also, I think, given the difficulty of doing it manually, the focal distance ought to automatically set itself to the distance from the selected camera to the selected object when you bring up the Render Options screen (or there ought to be a button to load it). Better lighting would have been nice, but things like area lights and true global illumination do come at the expense of render time.