http://www.theinquirer.net/?article=28341


BACK IN September, ATI told us that you need more per pixel operations then you need textures. It’s the ratio that changed over the years, but we don’t want to make a history class of this article. It said that it believes that the industry should go that way. Nvidia, on the other hand, believes in different ratios between pixels and textures.
We finally confirmed that ATI's upcoming R580 GPU will again have sixteen pipelines only but this time it will have 48 Pixel Shader units. What does that mean?

Well, it's not the easiest subject to explain, but pipelines in this case can be associated with a job done by texture memory units.

In the R580 case, the chip has 16 traditional pipelines that can process 16 textures while at the same time it can calculate 48 pixel data. The RV530 marchitecture is a good way to understand what ATI is doing now. With this chip, you have 12 pixel Shaders but just four texture memory units. Its a 3:1 ratio, as ATI believes that you need that many pixel information compared to textures.

In R520 for example ATI is using 16 pixel shaders, pipelines and has 16 matching texture memory units. In perfect scenario in each clock you can get 16 textures over 16 pipelines. Nvidia's G70 has 24 pipelines, let's call them pixel Shaders but it can process 16 textures. Nvidia is using a 3:2 ratio, as it believes that just need a little bit more pixels than textures.

We strongly believe that Nvidia is going to increase the number of its pixel operations and texture units in its upcoming G71 GPU. We believe it might move to 32 pixels/pipelines and 24 TMUs but we cannot confirm this at press time.

This might bring us back to the times when graphic companies will pressure developers to program for their hardware. It will be their choice to use 3:2 Nvidia's pixel to texture ratio or 3:1, which is what ATI wants to do. Nvidia spends more money in its TWIMTBP, The Way Its Meant To Be Played so it might win more of these battles.