I couldn't use poser 5 on my machine. could a bit more when SR4 came out. However I found it better to go backward so I bought Poser 4 and ProPack and quit using Poser 5. I got poser 6 on the special upgrade and just couldn't pass it up (was like $60 or something as a special upgrade). I have quit using all my other versions of Poser now, and only use Poser 6. I love it, it works, and a very plesant experience. New cool feature of Poser 6 is partial rendering you can render just a part to see a change in your scene and then render the full when your ready, saves time as well as helps with the multiple rending thingy. Really is a good release of poser.