The new OCZ "GeForce 8800 GTX GPU" is identical with Nvidia's reference 8800 GTX board, using a 575 MHz core and 1350 MHz memory clock.
Taken from here.
8800 GTX's use a 900 MHz (1800 MHz effective) memory clock. I think when NVidia switches to GDDR4, the cards will see a substantial performance increase because the G80s really rely on the high memory speeds for performance (because of the single action per clock cycle on the unified shaders).