I noticed the same slow downs and I'm not even rendering. I have to cut my preview mode down to solid fill or wire frame to get even close the same speed as fast track texture preview mode in P4. In fact I resort to P4 for 90% of my work. Even loading one figure in p5 and revolving around it in preview mode (not rendering) is almost half the speed of P4 in the same preview mode. Now people keep asking system specs. Quite frankly that's irrelevant. Both p4 and p5 are run on the same machine which is an AMD 2200 with 1 gig of DDR ram and a gforce 3 card. Unless P5 is so huge an EXE that it eats up so much ram to cause disc swapping where P4 doesn't then both should run at the same speeds. I've even set the current render settings to p4 thinking if its set to fire fly that P5 is sending info to firefly to keep it updated even though it isn't rendering anything. I haven't noticed any improvement in the preview modes from p4 to p5 so its not like they added anything xtra. This makes p5 seriously useless to me. I work with large scenes with multiple figures (2 vickies, 4 mikes, several buildings and an entire city street scene with multiple car figures). Since I create comic book style material I have to render, pose, render, pose etc. Having a slow preview mode is a set back. Having to wait even longer for a render makes p4 much more appealing than p5. And I don't even dare try and put in any dynamic hair or clothes.