I just emailed Curious Labs tech support about Poser5. I asked them if the code for it was optimised for Pentium4's, as Poser4 was not because it was witten before Pentium4s existed. They said it HAD NOT been optimised to run on a Pentium 4. So, if you have a Pentium 4 are wer thinking about buying Poser5 because you think it will render a lot faster etc... I my opinion, I wouldn't buy it on that basis, as it won't fully be utilising your P4 just like Poser4.