John Carmack Talks ATi Radeon 8500

Discussion in 'Beyond3D News' started by Dave Baumann, Feb 24, 2002.

  1. Dave Baumann

    Dave Baumann Gamerscore Wh...
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    Jan 29, 2002
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    O Canada!
    John Carmack has put up a new .plan update that primarily deals with the support he’s added for ATi’s Radeon 8500 series in the new Doom engine. As ever he’s suffered the usual ATi driver issues, although he say’s ATi are quite responsive in resolving them, however here are a few of the highlights on the 8500’s hardware capabilities in relation to the new game engine:

    On Radeon 8500’s Pixel Shader / Multitexturing support (classified as PS1.4 under DirectX):

    <BLOCKQUOTE>The fragment level processing is clearly way better on the 8500 than on the Nvidia products, including the latest GF4. You have six individual textures, but you can access the textures twice, giving up to eleven possible texture accesses in a single pass, and the dependent texture operation is much more sensible. This wound up being a perfect fit for Doom, because the standard path could be implemented with six unique textures, but required one texture (a normalization cube map) to be accessed twice. The vast majority of Doom light / surface interaction rendering will be a single pass on the 8500, in contrast to two or three passes, depending on the number of color components in a light, for GF3/GF4 (*note GF4 bitching later on).</BLOCKQUOTE>
    On Radeon 8500’s Vertex Shader throughput:

    <BLOCKQUOTE>A high polygon count scene that was more representative of real game graphics under heavy load gave a surprising result. I was expecting ATI to clobber Nvidia here due to the much lower triangle count and MUCH lower state change functional overhead from the single pass interaction rendering, but they came out slower. ATI has identified an issue that is likely causing the unexpected performance, but it may not be something that can be worked around on current hardware.</BLOCKQUOTE>
    Along with Brain Hook (here and here) John is the latest to voice his discontent over GeForce4 MX’s naming.

    Read the full .plan update here.

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