Diamond X1900XTX Video Card Review :: Diamond X1900XTX Features

• 90 nanometer low-k process
• 384 million transistors
• 48 Pixel Shader Processors
• 8 Vertex Shader Processors
• 16 ROPs
• DirectX 9.0c
• Pixel Shader 3.0
• Vertex Shader 3.0
• HDR
• up to 6X Multisample Sparse Sample Anti-Aliasing
• Up to 16x Anisotropic Filtering
• 512-bit Ring Bus memory controller
• Render to Vertex Buffer
• 648MHz Core clock speed
• 774 Memory clock Speed (1.548GHz effective)
• Crossfire

Key features of the X1900XTX include support for Pixel Shader 3.0 and Vertex Shader 3.0. Every video card available today, with the exception of some X800 series cards and integrated graphics support this standard, introduced with Microsoft's DirectX 9.0 API in late 2002.

The X1900 differs from the previous high-end in having 48 Pixel Shader Processors. This triples the number of shading power compared to the X1800XT. Games are getting more and more Shader intensive and the increase in PSPs should give an advantage in games like Oblivion and Stalker due later this year. The number of outputted pixels is the same as the X1800, 16. The X1900XTX has 8 Vertex Shader Pipelines, meaning that the card is capable of over a billion vertices a second theoretically.

Pixel Shader 3.0 differs from 2.0 in the following matters: nearly unlimited Shader program lengths (versus 96 in 2.0), Floating Point 32-bit color processing throughout the pipeline (versus 24-bit precision in the previous generation), a back-face register for two sided lighting and more. Games like Oblivion use Pixel Shaders in the materials, in the skin, in almost any surface.

Vertex Shader 3.0 is a small improvement over 2.0. Key new features of Vertex Shader 3.0 include nearly unlimited shader length programs (65,536 versus 256), dynamic branching, render to texturing and more. Vertex Shaders can be used to give realistic animation, displacement mapping and more. Oblivion uses vertex shaders to mimic the talking heads, in the grass and in nearly every scene.

HDR stands for High Dynamic Range lighting. The advent of floating point hardware allows for higher ranges of contrast between the brightest light and the darkest dark. Games like Far Cry use HDR to give the sky a more natural look. HL2 Lost Coast uses HDR to give a more realistic sheen to rocks, the sky and more. Oblivion uses HDR in every scene. The game has a wide variety of areas that benefit including when sunshine shines through a stained glass window.

NVIDIA introduced Transparency Anti-Aliasing with their 7800 series of cards last year. TAA adds either MSAA or SSAA to transparent textures, lessening problems like a moire pattern in a fence or dense vegetation. The X1900XTX and other X1K series cards apply SuperSampling to those transparent textures and MSAA to everything else.

ATI calls their Multi-GPU technology Crossfire. The X1900XTX is Crossfire-ready. To enable Crossfire all you need is a X1900 Crossfire Edition master card, a compatible motherboard and a Crossfire cable. Install the two cards into two PCI Express X16 slots, attach the cable to the cards and the monitor cable, turn on the computer and install the drivers. I was able to test it with the Diamond X1900XTX and a ATI Crossfire Edition master card.

Diamond decided to clock the video card at the same clock as ATI's reference X1900XTX card, 648MHz for the core and 1.55GHz for the memory. Using ATI's Overdrive, I was able to successfully overclock the card to 689/1.6GHz, a overclock of 41MHz core/50MHz for the memory. The card was totally stable at this clock speed, not bad.

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