Geforce 8600GTS works at 675 MHz default speed and the 128 bit memory works at 2000 MHz. The Shader units on this chips works at 1.5 GHz shaderclock. The chip has 24 Texture memory units, eight ROPs and 32 unified Shaders.
In theoretical numbers the card can score 216 GFLOPs, 15600Mtex/s, 5200 Megapixels/second
The overclocked cards certainly can do even more.