Pixel Shader Performance
The above-mentioned MDolenc Fillrate Tester can be employed to benchmark the performance of modern graphics cards at executing pixel shaders:
It’s all natural here: the advanced architecture and high clock rate of the GeForce 6600 GT win the test, leaving the RADEON 9800 XT, once unrivalled, behind. The graph of the 6600 GT has a similar shape to that of the GeForce 6800 GT, but the latter has higher results, of course.
What’s curious, the new GPU doesn’t have exactly half the performance of the GeForce 6800 GT, but rather more, due to its higher core frequency.
The results suggest that the GeForce 6600 GT, like all the new GPUs from NVIDIA, executes pixel shaders faster at half the calculation precision.
Disabling Z writes brings no surprises: all the above-said things are true for the diagram above.
Color writes disabled, we again see “miracles”: the GeForce 6600 GT produces a predictable result when calculating per-pixel lighting, but reaches the level of the GeForce 6800 GT and more at executing simple pixel shaders!
Next we tested the new NVIDIA GPU in our Xbitmark suite, which allows evaluating the performance of the GPU at executing pixel shaders of various degree of complexity.
The GeForce 6600 GT is slower than the RADEON 9800 XT in one case (the Factored BRDF + HDR shader is “heavy” in terms of arithmetic computations) out of fifteen. Well, the advantage of the newer model over the older solution was rather small with complex shaders like Dot Product Bump Mapping + Specular + Reflection, Metal + Phong, Cook-Torrance + Texture + Fresnel and Wood.
Anyway, the new graphics processor from NVIDIA looks very strong in this test. The NV40 architecture, which is a foundation of the NV43 core (i.e. of the GeForce 6600/6600 GT GPUs) has no clearly weak aspects like the NV3x architecture had (particularly, in pixel shader performance).
Now, let’s proceed to pixel shader tests from 3DMark 2001SE and 3DMark03 suites:
The performance of the GeForce 6600 GT with version 1.1 pixel shaders is worse than that of the RADEON 9800 XT, which is greatly helped by its 256-bit memory bus.
The GeForce 6600 GT is better at executing version 1.4 pixel shaders – it is only slower than the GeForce 6800 GT, a GPU of a higher class.
3DMark also testifies to the exceptional performance of the GeForce 6600 GT, confirming the results of Xbitmark and MDolenc Fillrate Tester.