I used Poser 5 with 256m and poser 7 with 512 M and they run ok. 6 figures in a scene slow it down some but not to the point its unusable . You do need to check your setting for virtual memory (page file) since the default setting is too low . If you have disk space just set it for system managed and leave it .

I cant comment on Vue , but I use Bryce, Carrara and lightwave and they all work fine .

If you have the memory slot and some spare cash adding an extra meg of memory to your system when its on sale will help overall performance . even 512 would be good .