Description So far the release of graphics chips has centered around their ability to support various features of DirectX. In the past both leading graphics companies had, at some time or another the edge over their rival. It is now becoming apparent that, for the first time in quite a while, DirectX 9.1, expected around Spring 2003, will offer features which will not be supported by the latest offerings by ATI and nVidia.
The main feature of DirectX which has prompted much of the competition between the two graphics companies, has been their products' support for versions of Pixel Shader, part of DirectX's Application Programming Interface. It was nVidia who first used the release of Pixel Shader 1.1 to their advantage when ATI's new card, at the time, the RADEON 7200 supported only version 1.0. The same thing happened to nVidia when DirectX 8.1 was released carrying support for Pixel Shader 1.4. Its release meant that the GeForce 3 offered support for DirectX 8.0 but not 8.1.
In order to better understand what will happen with DirectX 9 you have to consider that both the RADEON 9700 Pro and NV30, are called DirectX 9.1 hardware. Their support however, will extend only as far as Pixel Shader 2.0, while Microsoft's DirectX 9.1 will feature Pixel Shader 3.0. The upcoming R350 and NV35, from ATI and nVidia respectively, expected to appear in spring 2003, will most probably not carry Pixel Shader 3.0 support. So when the bug fixing DirectX 9.1 is released both manufacturers will find their offerings supporting DX 9.1 but not quite.
The logic behind releasing new versions of Pixel Shader before they are fully supported by hardware is a sound one. It allows programmers time to get accustomed to the new model, theoretically, increasesing the rate at which that model is utilised. So for all of us that should result in better looking games.
