Go with Poser Pro 2012. I used to routinely have problems rendering more than three or four fully-dressed figures in a room full of props using Poser 8, but when I went to Poser Pro 2010 on a 64-bit machine (with 24 GB RAM and six-physical/12-virtual cores) I was able to manage about 20 figures with no problem. (Although the pose room was very slow.) Poser Pro 2012 is even a little better on the memory management.