An 8600GTS is five tiers up on Cleeve's performance table, and would make a big difference. Still, if you want to play the newest games on high settings, you'll need to go even higher, which will require a PSU upgrade. I can't view its picture here at work, but if it isn't a standard ATX-sized PSU, you might need a new case as well.
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There is ALWAYS a drone. Exactly where, or how many drones you will encounter may vary, but that there will be at least one will not.