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Performance in Theoretical Benchmarks: Fillrate Examination

As usual we will start the theoretical tests with the fillrate investigation. Let’s check if the claimed number of 2.2GPixels is true. At first come the data obtained with disabled multi-texturing:

Low VPU frequency does its dirty deed: the newcomer falls behind all the rivals. With enabled FSAA the fillrate is considerably lower: all the competitors use a more optimal multisampling mode, while DeltaChrome uses supersampling.

Now let’s enable multi-texturing:

As you see, DeltaChrome shows results, which are very close to the theoretical ones. 8 rendering pipelines allow the newcomer to outperform all the competitors. Even RADEON 9600 XT with the VPU working at shy-high 500MHz frequency couldn’t demonstrate such impressive performance. Unfortunately, with enabled FSAA the solution from S3 lost its positions immediately. This diagram can actually be a perfect illustration to an article about the advantages of contemporary FSAA methods.

Now we are going to test the new product with the help of a special test utility, which we have already introduced to you in our article called ATI RADEON 9600 XT vs. NVIDIA GeForce FX5700 Ultra. Here is the result obtained with color writes and Z writes enabled:

As you see, starting with two textures DeltaChrome outperforms the rivals, which is not at all surprising keeping in mind its 8-pipeline architecture. The remarkable thing is that DeltaChrome runs pretty fast when it works only with the Z-buffer, however, even when it has to lay only one single texture the fillrate drops by about 50% below the maximum theoretical value of 2400 Mpixels/sec. The chip probably has not very big texture caches and the caching algorithms it uses for textures, pixels and Z-buffer is not as optimal as the competitors’ solutions.

However, there is actually nothing to be surprised at. ATI and NVIDIA have already released a few generations of successful graphics processors, while S3Graphics can only boast Savage4 and Savage2000.

With disabled Z writes the results looked as follows:

The graphics accelerators from ATI and NVIDIA hardly even noticed that Z writes got disabled, however, DeltaChrome reacted in an absolutely different manner: with no textures the fillrate dropped quite significantly. Now let’s enable Z writes and disable color writes:

Again the picture is pretty unexpected: DeltaChrome loses its advantage in case of more than 1 texture, while all other testing participants do not notice this change at all. The maximum performance can be achieved in case of no textures and in case of only 1 texture. I should say that DeltaChrome behaves very strangely: the results show that it still continues working on the textures even when the color writes is disabled. Moreover, the results achieved in this case are hardly related to those obtained with enabled color writes. Hopefully this can be cured in the next driver versions. Although I cannot quite understand why the driver can matter at all for a low-level benchmark like that, if the graphics processor architecture is adequate enough.

 
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