Radeon X1800 XL is the best you can get.  I recently ordered one for a friend who wanted me to build him a pc.  This beauty runs any game in the world.  It even looks beautiful... I almost cried when I saw it.  You can see details about the card here

http://www.ati.com/products/RadeonX1800/

Overview & Features

Radeon® X1800 Series — Ultra-threaded 3D Architecture for Maximum Visual Velocity

This is it. The new Radeon® X1800 Series hands you the visual and performance possibilities you only dreamed of from a PC graphics processor. It has been designed with a radically new ultra-threaded 3D architecture and Shader Model 3.0, unleashing the most mind-blowing gaming effects. What’s more, the X1800 introduces ATI’s revolutionary Avivo™, our new reference for video and display perfection.

Featured on this page:

        * The Most Advanced 3D Performance Arsenal
        * CrossFire™ : Multiply and Conquer with Multi-GPU Performance
        * High Definition Image Quality with Avivo
        * ATI’s Catalyst® Power and Control

The Most Advanced 3D Performance Arsenal
Get the ultimate gaming performance AND image quality with an advanced ultra-threaded 3D architecture, a ruthlessly efficient memory controller and Shader Model 3.0, all enabled by the most advanced 90 nanometer GPU process.

    * Radeon X1800 Series excels with Shader Model 3.0, HDR and adaptive anti-aliasing

      Radeon X1800 series’ 90-nanometer process technology and ultra-threaded architecture combine power and efficiency as well as support for Shader Model 3.0 to deliver new High Dynamic Range visual effects, enhanced realism with Adaptive Anti Aliasing and lightening fast performance in OpenGL and DirectX® 9 games.

CrossFire: Multiply and Conquer with Multi-GPU Performance
Designed from the ground up with GPU sharing in mind, the Radeon X1800 series allows you to get incredible gaming performance by adding a Radeon X1800 Crossfire Edition graphics card for ultra fast performance that works with all games, all the time.

    * Supertiling for optimized gaming performance

      CrossFire’s “supertiling” GPU sharing speeds rendering by evenly dividing the graphics processing, intelligently alternating the rendering workload to each Radeon GPU for efficient load balancing, and optimized performance.
    * CrossFire boosts image quality

      CrossFire boosts image quality along with rendering speed, eliminating the need to crank down screen resolutions to get the high image quality you want.

      CrossFire ignites with the higher anti-aliasing, anisotropic filtering, shading, and texture settings you desire. Adjust your display configurations, experiment with your advanced 3D settings, and check the effect with a real-time 3D-rendered preview within ATI’s Catalyst Control Center to rule your CrossFire system.
    * Upgradeable components and web support

      CrossFire supports a wide range of ATI-based graphics cards and motherboards, and offers compatibility with a broad array of third party components for a flexible and robust solution.
          o Upgradeable components allow you to gradually improve your system performance with the reliability and support that only ATI delivers.
          o Free monthly on-line Catalyst software updates, ATI’s one-click comprehensive help system, and web-based online customer support are available 24 hours per day.

High Definition Image Quality with Avivo
Connect your Radeon X1800 with your home entertainment devices for high definition convergence, enhanced with ATI’s revolutionary new Avivo video and display technology platform. Avivo technology creates vibrant colors, ultra sharp images, true-to-life image reproduction, and the smoothest HD video playback ever offered by ATI.

Avivo redefines the ultimate visual experience for today’s PCs, and sets the stage for tomorrow’s exciting possibilities. Check your board for specific support of Avivo features.

    * Sharp video and photos

      Avivo enhances your digital video and photos, creating sharp images, crisp text, and vivid color. Boost the video quality captured by your Media PC and Personal Video Recorder with advanced 3D comb filtering and automatic gain control. Improve analog video signal quality and reduce annoying artifacts. Maintain clean images even at high display resolutions with Avivo’s video scaling technology.
    * True-to-Life Image Reproduction

      Get high image fidelity with CRT and LCD displays, TVs, rear projection and plasma TVs, as well as projectors. Avivo introduces new life to colors across the entire spectrum with an advanced 10-bit-per-color display engine. Gain better digital signal reception, and maintain cleaner video with hardware noise reduction. Enjoy high-quality analog video capture enabled by robust 12-bit analog-to-digital converters.
    * Smooth Video Playback

      Free your CPU to devote more processing power to other applications with Avivo’s hardware accelerated processing of new HD video formats, including H.264. Transform your movies and improve every image sent to your display with hardware post processing for superb stutter-free viewing. Avivo gives your video playback the smooth, fluid motion you want from your HD content.
    * Universal Display Connectivity

      Certain ATI graphics cards with Avivo technology can dissolve connectivity barriers between PCs and consumer electronic devices. Outputs for virtually any TV via analog or digital interface, such as s-video, and DVI , are complemented by inputs for cable, broadcast TV and other video sources. And advanced dual-link DVI interfaces support the largest high-resolution LCD displays.

ATI’s Catalyst: Power and Control
Control your Radeon X1800 with ATI’s Catalyst Control Center, the award winning feature-rich and stable 3D software application. Catalyst automatically configures optimal settings for your system, and is packed with features that go far beyond traditional driver configuration software.

    * Experiment with display settings hassle-free

      Adjust your display configurations, experiment with your advanced 3D settings, and check the effect with a real-time 3D-rendered preview.
    * Support and updates for performance and protection

      Catalyst supports GPU overdrive, and automatically resets the graphics processor when necessary. Keep ahead of fast-moving gaming effects and technology changes with frequent Catalyst software updates, and discover Radeon X1800’s exceptional support for Windows® XP, Windows® Media Center Edition and Microsoft® Vista™.

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