Well, I have not run into problems importing Poser files. I have thrown pretty much everything I have at Carrara 5Pro and have had multi hi rez figures in one scene and still have not been able to choke Carrara. I have slowed down the render time but that is to be expected with the lighting i use.

Sounds more like someone has computer issues, more than a Carrara problem. So you know, before the Flame. I only have a AMD 2.0GHz with only 768 MB ram.