Speed Costs Money, How Fast to You Want to Go....?
There is a massive uptick in gaming performance going to an 8600 series card.
Nvidia claims a 5X improvement over onboard with the 8500s, but a 13X boost from a 8600 card. I understand money is always an issue, but even if you run your 8500 at near melting, it won't come near the oomph of the 8600.