I'm running Win2k Pro SP2 with only 128 MB ram on a Celeron 700 (20gb HD - 9 GB free)... Poser runs great except for the fact that I try to render high res images with high res maps on occasion. My Poser Directory is only about 2.5 gigs. I get a few errors every now and then about the "Display size is too large. Creating the next best thing" and poser doesn't show the actual owrkspace. Other than those 2 things poser runs pretty fast on my comp. Also make sure there isn't other memory consuming apps running. Poser don't like any other apps running, on my machine anyway.