ATI confirms no Shader 3.0 in Radeon X800

Future is 3Dc 'normal map' compression

ATI is banking on new texture map compression technology to drive demand for its Radeon X800 graphics chips - aka R420 - rather than support for the DirectX 9.0 API's most up-to-date shader systems.

And, as anticipated, the Radeon X800 Pro, which ATI launched today, does not support DirectX 9's Pixel Shader 3.0 - unlike its rival, the GeForce 6800, unveiled by Nvidia last month.

Instead, ATI believes that its 3Dc technology will prove of more use to games developers and games players alike.

The new code allows games developers to compress 'normal maps' by a factor of four to one. Normal maps are used to apply a high level of detail to 3D characters, allowing developers to produce visually complex entities without the need to construct them out of large, processor-unfriendly and memory-consuming numbers of polygons.

Normal maps are increasingly being harnessed by games developers - the likes of Doom 3 and Half Life 2 make extensive use of the technology - but memory limitations remain. ATI believes that 3Dc will allow coders to exploit normal map technology to the full.

Radeon X800 3Dc and Serious Sam 2

Serious Sam 2 with 3Dc enabled (left) and disabled (right)

That, the company claims, will be far more value to developers than version three shaders, which provide no visual enhancements over version two and so far only promise a performance gain over their predecessors.

Unlike ATI, Nvidia has put version three shaders at the heart of its next-generation chip, NV40, the basis for the GeForce 6800 and 6800 Ultra. Games that support Pixel and Vertex Shader 3.0 are a long way off - far enough, ATI hopes, for it to focus on enhancing the performance of Pixel and Vertex Shader 2.0.

ATI claims X800 chips process pixels faster than the GeForce 6800 series, particularly as pixel shader routines become more complex. That leaves Nvidia relying heavily on whatever performance gains Shader 3.0 can yield, and that is unproven, ATI European developer relations chief Richard Huddy told The Register.

And it's likely to remain unproven for some time, if what games developers tell him is anything to go by. His personal hunch is that games developers will not go beyond Shader 2.0 technology until Shader 4.0 arrives with the next major Windows revision, 'Longhorn', and that may not happen until 2006.

That still leaves Nvidia with an advantage: NV40 is future proof, and it coffers are large enough to encompass enticements to persuade games developers to support Shader 3.0. The visual benefits may be limited, but there is value in being able to say you're at the forefront of games technology.

Even if that happens, ATI is assuming it has still time within its on-going launch schedule to offer a Shader 3.0 supporting GPU - and it will have had a longer time than Nvidia has to perfect it. ®

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ATI 'drops pixel, vertex shader 3.0 support' from R420
ATI R420 slips from April to May
ATI 'to ship R420 as Radeon X800'
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