If you can afford to up your RAM to at least 512, I would recommend 1G, then Poser 5 is about as stable as Poser 4 in most circumstances. There are a few tips to watch out for-- you cannot cancel renders to a larger window, that's an automatic freeze. Some rooms are problematical. I don't use the Face room, though it's possible just not what it was made out to be, a bit more of a toy. If you plan to do animations, get Poser 4. Poser 5 is not animation ready for most people. However, I love the FireFly engine and would not readily give it up, I also adore the library system and the abilty to have more than one runtime linked to Poser, not to mention embedded folders that you can arrange as you like to give you a better notion of what you have to work with. The material room is involved but gives you a lot of control over your settings, including reflection, refraction and much better water scenes. However, if you plan to use Vicki3, I would again strongly suggest a Ram upgrade. She is right at the margin of what the Poser Engine can handle. Other than that-- some people can get large scenes out of Poser 5, I can't, have to do it in sections. I bought Poser 4 with Vue,and ended never quite understanding Vue, so that was not such a good buy for me. I am a bit older, I learn somewhat slower, and I had poser 4 for a year before I bought Poser 5. I did not find much of Poser 5 difficult to understand. I still don't know how to clothify but I'm lazy.:)) Emily