Geometry Performance

Here are the geometry performance differences between the boards using a Difuse + Specular Lighting test from RightMarkD3D

ATI R580 Geometry Performance

  Fixed Function T&L  VS1.1  VS2.0  VS2.0 Static FC  VS2.x Dynamic FC 
X1900 XTX  91.2  87.7  87.5  81.2  55.6 
X1800 XT  87.2  84.2  84.7  77.7  53.4 
X850 XT PE  59.9  58.3  58.3  51.7   

frames per second

ATI R580 Geometry Performance Diff

  Fixed Function T&L  VS1.1  VS2.0  VS2.0 Static FC  VS2.x Dynamic FC 
X1900 XTX to X1800 XT  4.6%  4.1%  3.4%  4.5%  4.1% 
X1900 XTX to X850 XT PE  52.3%  50.3%  50.1%  56.9%   

percentage

The performance differences between the X1900 XTX and X1800 XT herald no surprises as they are roughly around their difference in theoretical rates, indicating that there are no alteration to the vertex shader engines. The performance difference between the X1900 and X850 is in the 50%-60% range, but for the most part this is a little below their theoretical rate differences.

ATI R580 Geometry Performance 2

  Ambient  Diffuse (1 point light)  Diffuse (2 point lights)  Diffuse (3 point lights)  Diffuse + specular (1 point light)  Diffuse + specular (2 point lights) 
X1900 XTX  307.0  231.9  160.9  122.4  149.1  84.9 
X1800 XT  293.6  227.9  154.2  117.7  143.9  81.9 
X850 XT PE  141.9  140.5  98.0  79.5  113.5  68.5 

frames per second

ATI R580 Geometry Performance 2 Diff

  Ambient  Diffuse (1 point light)  Diffuse (2 point lights)  Diffuse (3 point lights)  Diffuse + specular (1 point light)  Diffuse + specular (2 point lights) 
X1900 XTX to X1800 XT  4.6%  1.8%  4.4%  4.0%  3.6%  3.7% 
X1900 XTX to X850 XT PE  116.3%  65.1%  64.1%  54.0%  31.3%  23.9% 

percentage

Again, with the range of differenct vertex shader operations here the performance differences between the X1900 XTX and X1800 XT are hovering around their theoretical differences. The performance differences between the X1900 and X850 are a little different though, with the ambient test favouring the X1900 significantly, while the specular tests favouring the X850 architecture, such that it has a performance deficit here that's less than their theoretical differences.