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ATI All In Wonder X1800XL Video Card Review :: AIW X1800XL Features
The X1800XL is based upon ATI's R520 architecture. ATI has gone the extra mile in getting performance out of their next generation core with over 321 million transistors on 90 low-k dielectric nanometer processes. To put that into perspective, the previous X850XT PE the X1800 is replacing has 160 million transistors and is built upon TSMC's 130 nanometer process. ATI has until the release of the X1K series been Shader Model 2.0 compliant with their video cards. The X850XT PE shares the same basic architecture as the 9700 Pro from 2002. Microsoft releases a new API (Application Programming Interface) called DirectX every year or two. With the release of DirectX 9.0, Microsoft included Pixel and Vertex Shader 2.0 and 3.0 versions, allowing for future expandability. The X1800 is fully Pixel Shader 3.0 compliant. Pixel Shaders are small programs performed on pixels to give special effects. Most games use Pixel Shaders to give beautiful water in games. Other effects PS can do include metallic paint, shiny reflective armor and more. Pixel Shader 3.0 has the following improvements over PS 2.0: nearly unlimited shader lengths, dynamic branching and looping, increased constant counts, support for a back-face register, 32-bit floating point precision per component throughout the pipeline, and Shader antialiasing. ATI says their R520 architecture is Shader Model 3.0 done right. ATI has an "Ultra Threaded Dispatch Processor". Pixel Shader programs are performed in batches of threads. The X1800XL has the ability to work on 512 threads simultaneously. ATI says this should allow for fine granularity of complex Pixel Shader programs allowing for excellent efficiency. One of the problems with modern video cards today is the lack of efficiency. ATI claims their X1K cards are 90% efficient. Vertex Shaders are programs performed on vertices. ATI's X1800XL is Vertex Shader 3.0 compliant. Key features of VS 3.0 include: nearly unlimited shader lengths, dynamic branching and looping, render to texture, and more. The X1800XL is capable of doing over 512 vertex shader instructions in a single pass, with 2 vertices outputted per clock. This provides up to 1 billion vertices in a second. One of the big issues with NVIDIA 7800GTX is shimmering in games when anisotropic filtering is applied. ATI says reviewers tend to use Quality mode when reviewing games. My opinion is any competent reviewer would use High Quality mode when reviewing. I won't go into the politics about reviewing $499 cards without using the maximum possible settings, but I feel no 7800GTX user or 7800GT user would use Quality mode in any event, as the performance with HQ mode is excellent. Full Scene Anti Aliasing first came into the forefront with the Voodoo 5 5500 and its Rotated Grid SuperSample Anti-Aliasing. NVIDIA and ATI have also supported AA in their video cards for years, but the state of the art of AA has been very stagnant. Sure, sample patterns have changed and multiple sample AA has been introduced, but the quality of AA has not improved much until the launch of the GEFORCE 7800GTX. NVIDIA introduced Transparency AntiAliasing to cure artifacts with transparent textures. ATI calls their version, Adaptive AntiAliasing. What ATI does is apply SuperSample AA to the transparent textures and MultiSample AA to everything else. Here are two pictures comparing AAA with without AAA. Notice in the two pictures, how the links in the fence appear like a mess without Adaptive AntiAliasing enabled, while the picture with Adaptive Antialiasing enabled clears up the picture on the links.  No AAA  4x AAA Computer monitors are mostly limited in the range of contrasts it can display. Graphics cards before the advent of floating point color only had a range of 255:1 (8-bits per color component).The problem is the human eye can distinguish between a range much higher than that. High Dynamic Range lighting in games can dramatically affect the lighting of a game. Far Cry was the first modern game to use HDR, in the form of Blooming. Blooming is an effect similar to that of walking into bright sunshine from a dark house. Valve released Half Life 2 last year about this time. Recently, they released a one level demo with HDR support. Here are a few screenshots from Far Cry and HL2 Lost Coast to show HDR. ATI's solution is the only one to fully support HDR+FSAA at the same time in all situations, something NVIDIA's 512MB 7800GTX can't do.  No HDR  Blooming  Full HDR Contents:Discuss This Article
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