I have a two year old Dell P4 2gig processor running a GeForce 2 card with a gig of ram. For Apo it depends on what I'm doing with the image. If it's a normal post I run at 4000x3000 at 500 dpi. If I'm going to put it up for print, I run at 5500x3667 at 2000 dpi. I've ran experiments on oversampling and personally, I think anything over 1 is a waste of render time. People might disagree with that, so run some experiments and see what works best for you. Another thing that you might think about is using some of your hard drive as virtual memory. I have two drives partitioned up into over half a dozen sections. Most of those are contributing to virtual memory. I've noticed it helps the response and render time in Apo.