I have 4 gigs as well. Poser isn't too sluggish (I used to have only 500 mb). With windows XP as my operating system, I don't think it can handle more than 4 gigs anyway. My 3d  modeling programs seem to run out of memory constantly though. But poser not so much. It seems to be much hungrier for processing power.

Instead of memory, I'd like to have a quad core system. All that processing power would really speed up the renders.

D'oh! Why do things that happen to stupid people keep happening to me?