Performance of ATI RADEON X800 in Synthetic Benchmarks

Synthetic Benchmarks: Fillrate tests

The synthetic benchmarks tests will as always start with the fillrate and texturing speed, which we will test with the help of McDolenc Fillrate Tester. The same benchmark allows estimating the graphics cards performance during the processing of simple DirectX9 pixel shaders version 1.1 and 2.0.

The first test round with enabled color writes and Z brought extremely disappointing results. It was not the RADEON X800 XT but the graphics card based on NVIDIA GeForce 6800 Ultra that appeared the leader in texturing speed, even though we had expected the opposite bearing in mind the ability of the newcomer to process 16 pixels per clock and its higher clock frequency of 520MHz.

The curve of RADEON X800 XT indicating the fillrate drop as the number of textures increases, is very similar to the curve obtained for GeForce 6800 Ultra. But if they both run neck and neck in case of  no textures, then with the increase in the number of textures RADEON X800 XT falls behind the rival.

If we calculate the efficiency of the RADEON X800 XT and GeForce 6800 Ultra as a ratio between the practical result and theoretical result, considering the situation when each new texture requires an additional clock cycle as a reference point, then we will see that GeForce 6800 Ultra approaches its theoretical maximum as the number of textures increases, while RADEON X800 XT gets away from its theoretical maximum. Moreover, in the heaviest case, when there are 4 textures to be laid, the efficiency of NVIDIA GeForce 6800 Ultra calculated like that will make about 89%, while for RADEON X800 XT it will be only around 49%.

It looks like the efficiency of these graphics cards during simple texturing procedure is limited by completely different factors.

By GeForce 6800 Ultra the reason is probably connected with the insufficient bandwidth of the memory bus: as the number of textures increases, the number of clock cycles required to process each pixel group also grows up, and hence the memory workload reduces thus making the performance approach the theoretical maximum

BY RADEON X800 XT it is completely the opposite. As the number of textures increases, the efficiency drops down, which indicates that RADEON X800 XT has some problems with the textures sampling speed or the ability of the texturing pipeline to hide the latencies of the texture samples.

The graph for RADEON 9800 PRO is remarkably similar to the graph for RADEON 9800 XT. At the same time RADEON X800 PRO behaves a bit differently than RADEON X800 XT: it is the least efficient in case of no textures or only one single texture, i.e. when the memory bus workload is the highest.