Before I upgraded, I was running Vue 6 Inf on a single core Sempron machine with 1.5 gigs of ram. . It was limited and slow, but it worked. You should have no problem if your scenes are modest.
 
One benefit of Vue (over Poser) is that you can decimate an object's poly count. Also don't be afraid to reduce texture sizes when you can get away with it. Just play with it! As you scale the learning curve, you will have many AHA! moments and will be amazed at what Vue can do for your Poser scenes.