Agree with BB, my rig is a celeron dual@2.0Ghz with only 2 gigs in ram, and I'm able to put, say 5 to 9 figures(this is counting clothes) an have the same speed... well that was made just to test, I usually work with 2 or 3, max 5 figures...
that rig isn't VEEEEERY expensive.
so if you're lookin foward to get a new rig...  first you might try to see how much money you can spend, and stick to it. nowadays computers are gettin cheaper every day.