Geometry Performance

Here we'll use RightMarkD3D to test the vertex shader performance of the 7800 GTX. First we'll look at the performance differences between the two boards under different shader profiles.

D3D RightMark (FPS) Fixed Function T&L VS1.1 VS2.0 VS2.0 Static FC VS2.x Dynamic FC VS3.0 Dynamic FC
7800 GTX 81.8 66.7 67.2 41.5 52.3 52.5
6800 Ultra 62.7 47.7 48.0 29.5 37.4 37.6

Fixed Function T&L VS1.1 VS2.0 VS2.0 Static FC VS2.x Dynamic FC VS3.0 Dynamic FC
7800 GTX % Faster than 6800 Ultra 30.4% 40.0% 39.9% 41.0% 39.7% 39.8%

In these tests the performance difference between the two boards is a little less than the increase in theoretical vertex rates, which doesn't necessarily point to much in the way of changes in the geometry pipeline beyond the extra two vertex shader units for G70.

We'll use RightMarkD3D again to test various different types of Vertex Shader program to see how these perform on the two boards. In all cases here the VS3.0 pipeline was utilised.

D3D RightMark - VS3.0 (FPS) Ambient Diffuse (1 point light) Diffuse (2 point lights) Diffuse (3 point lights) Diffuse + specular (1 point light) Diffuse + specular (2 point lights)
7800 GTX 250.3 104.7 74.4 57.2 96.2 68.0
6800 Ultra 165.0 77.5 53.3 40.6 69.1 48.9

Ambient Diffuse (1 point light) Diffuse (2 point lights) Diffuse (3 point lights) Diffuse + specular (1 point light) Diffuse + specular (2 point lights)
7800 GTX % Faster than 6800 Ultra 51.7% 35.2% 39.5% 40.8% 39.2% 39.2%

Most of the tests in this case indicate a similar pattern to the performance differences between the two boards under the various different shader profiles. However, in this instance we do see the Ambient test is slightly above the pure theoretical geometry performance differences, which does suggest that there are some changes to the Vertex Shader ALU's.