3DMark05
The Sapphire X800 XL is a leg up on the GeForce 6800GT with a 50Mhz which translates to a 800 megapixel increase in single texture fillerate. This works out to be slightly less in 3DMark however.
Pixel shading power goes to the 6800GT here though and the X800 XL trails by about the same gap that exists between it and the GeForce 6800.
Both the X800 and the X800 XL have the same number of vertex shaders and they run at the same clock speed so it is not surprising that both cards have the same vertex shading capability. Both the 6800GT and the 6800 trail by quite a big margin.