I use P5 on a lil ole G3 ibook with 640 gigs of ram...... Poser itself runs from an external drive (simply because I have a massively huge runtime that I didn't want to clutter my drive with) but it runs with no problems whatsoever. Sometimes a lil slow, and sometimes my puter does get a lil warm and the fan kicks on, but other than that, its all good! :D