I'm using a Pentium 333. Poser 5 seems to be working fine. I do have to wait at times, but since I haven't seen it on a faster machine I don't know if this is normal. I have been able to use the Face, Material, and the Hair room. haven't tried Cloth yet. Rendering works fine. It's a little faster than Poser 4. Oh... I have the ram at maximum, 384.