Nvidia has yet to introduce its G84 based cards. The Geforce 8500 GT is the first one and later Nvidia will follow with the 8400 GS and 8300 GS.
The funny part is that the driver that Nvidia released yesterday includes these yet to be announced cards. The Geforce 8600 GTS / GT, 8500 GT, 8400 GS and 8300 GS driver is not the same as the one for 8800 GTX/GT cards.
Actually it is, but for some reason you have to download the 8800 and the 8600 / 8500 drivers separatley. We wonder why. That is yet another surprise. This driver brings a new control panel and it works well.
The driver should be faster in many games and benchmarks, but Nvidia didn't go into much detail. You can get the XP one here and Vista 32 bit is here