Poser 4....Poser 5 locks up too much plus with P4 I can do other things while it renders...with P5, I have to shut down everything to use it if I'm going to use V3 or M3....and then still pray it won't lock up but it usually does. But I wish I could use P5 more successfully cause the folder situation is ridiculous in Poser 4. I have to have Windows Explorer open so I can count how far down the right pose folder is...LOL