I'm very new to this, so I may simply be doing something wrong; but I have one of the new Mac G4s; Poser works pretty well on it, but it did crash when I tried to work with more than 5 characters at the same time. As far as multitasking, when I have tried it with Poser up, the computer told me I didn't have enough memory. I recommend the new G4s, though-- the optical mouse is really cool...