It seems that nVidia has been modest regarding the GeForce 7800GTXs capabilities, allowing partners some freedom on their choice of clock speeds.
The original specs for the board mention default speeds of 420 MHz (GPU) and 1200 MHz (memory). Those specs would be adequate for most but in the search for the ultimate 3DMark score, some adjustments have been made.
The default board scores an impressive 7600 marks using a current AMD CPU while when part of an SLI setup, and the same CPU, it will deliver 11200 3DMarks. Now according to the inquirer.net, boards made by BFG, a U.S. nVidia partner, will deliver 460/1300 MHz. This improvement will apparently yield much better 3DMark scores. The BFG board will deliver 8500 3DMarks while in an SLI setup 13000 marks are guaranteed. The modest change in the figures does not seem enough for the change but the secret may lie in the CPU used for the testing. The BFG boards were tested in a setup that used an AMD FX57 CPU clocked at 2.8 GHz and although the changes in clock and memory speed are responsible for some of the increase, this should serve as proof of the importance of the CPU in gaming performance.
Still nVidia seems to have a good little card on its hands and ATIs R520 will have to be on its best behavior if it is to match it, let alone beat it. For those of you who still don't know the full specs (default) for the GF 7800 here they are:
430MHz Clock Speed
24 pixel pipelines
8 vertex shaders
Shader Model 3.0
256MB of RAM