When dealing with hair, RAM can be much more of a limitation than CPU speed, especially when rendering. During the beta phase of Poser 5, I upgraded my dual 533 Celeron from 320 to 576 MB RAM - biiig difference. Now I'm using a 1.3 GHz P3 with 512 MB most of the time - it's faster again, but the boost from 533->1300MHz felt less impressive than the one from 320->576MB.