Maybe the 8600GT has some juice in it?

cleeve

Illustrious
921MHz Core and 952MHz Memory with a simple pencil voltmod, yielding 6753 in 3dMar 06... a 44% increase over stock.

Now, there's finally a decent reason to buy an 8500 GT.... for a few select folks, anyway.

Looks like they might be a good overclocker's special... :)