ATI CrossFire Technology Showcase

When ATi announced their new CrossFire multi-GPU rendering technology months ago, it could have been viewed by many enthusiasts and the market as more of a reactionary response to NVIDIA's SLI multi-GPU technology than anything else.  When our preview showcase article was posted, hardware was still months away from being a reality and since then, only bits and pieces have leaked out on performance expectations.  Regardless, what looked good then on paper, certainly needed to be taken with a grain of salt and a dash of skepticism, since frankly no one could be certain of product performance claims without hardware in hand.  All the while, NVIDIA's SLI product offering and the all-important drivers that back it up, have been maturing and expanding breadth in support for virtually all game titles on the market now, through either predefined game profiles or user customized settings.

We were recently whisked away to sunny California for an Editor's Day press event to see ATi's next generation GPUs in action, but the week before we hit the road a Radeon X850 XT CrossFire kit was shipped to us from ATi for evaluation.  With an NDA lift date only a couple of short weeks away, the crunch was on, since the better part of one of those weeks was spent behind closed doors with ATi.

ATI Radeon X850 XT & CrossFire / Radeon XPress 200 Features & Specifications

ATI Radeon X850 XT Platinum Edition •_500MHz engine •_.13 micron copper low-k •_1GHz memory data rate •_256-bit memory interface •_256MB GDDR3 memory •_16 pixel pipes •_6 vertex pipes •_8 Gigapixel/second fill rate •_32 GB/s Peak Memory Bandwidth •_HYPER Z support for HD resolutions including Hierarchical Z, color and Z compression •_Hierarchical Z and Early Z •_Z Compression •_Fast Z Clear •_Z/Stencil Cache Six Vertex Engines •_Workstation class vertex processing power •_600 million polygon transforms per second •_5.7 billion vertex shader operations per second •_Workstation-class performance High-detail Geometry •_Designed for next-gen games with massive polygon counts •_Allows huge numbers of characters on screen at once •_High definition foliage and particle effects Smart Shader HD •_Long pixel shaders •_1536 instructions per pass •_High-detail geometry shaders •_Infinite length shaders (multipass via F-buffer) •_Single pass trig functions (Sine & Cosine) 3Dc Compression Technology •_Lossless Normal Map Compression •_4:1 Normal Map Compression technology SmoothVision HD •_Sparse sample pattern AA with gamma correction •_Temporal AA (up to 12X effective) •_Centroid AA •_16X Anisotropic filtering with adaptive heuristics HyperZ HD •_Optimized for performance at high display resolutions, including HDTV resolutions •_Lossless z-buffer compression (up to 48:1) •_Rejects up to 256 occluded pixels per clock •_Up to 32 Z/stencil operations/clock VideoShader HD •_High-quality video processing & acceleration •_Real-time user programmable video effects •_Video post processing and filtering •_MPEG 1, 2, 4 encode and decode acceleration •_FULLSTREAM Video Deblocking •_WMV9 decode acceleration •_High-quality resolution scaling •_Adaptive Per Pixel Deinterlacing •_Motion Compensation •_Noise removal filtering •_Display Rotation

The following dynamic rendering modes are available: • SuperTiling - CrossFire renders alternate 32x32 pixel squares in a fine-grained checkerboard pattern. This configuration increases image-rendering quality, as each card processes half of the complex 3D objects in the pixel squares. • Scissor Mode - each graphics card renders up to half of the display, either vertically or horizontally depending on the game or application. • Alternate Frame Rendering - the two graphics cards are used to render alternate frames of the display. This configuration increases the detail of the 3D objects each card can render, as each card handles half of the total number of frames. • Super Anti-aliasing - improves image quality by combining the results of full-screen anti-aliasing across two graphics cards in a CrossFire™ configuration. The two graphics cards work on different anti-aliasing patterns within each frame. RADEON XPRESS 200 Crossfire Edition •_ATI's first discrete PCI Express chipset for AMD K8 platforms •_Offers flexible platform design options for the mainstream and enthusiast markets •_Pin and BIOS compatible with onboard graphics platform Security and Reliability: •_TPM 1.1 & 1.2 support •_Improved security and authentication for: •_File storage, e-mail and personally identifiable information •_Remote Access and data decryption •_Broadcom enhanced Gigabit Ethernet w/ TPM •_Standards based TPM security for corporate networks •_RAID 1 support •_Higher date security with built in fault tolerance •_Improved capacity and performance •_AMD integrated enhanced Virus Protection technology Networking: •_Full support for Gigabit Ethernet and 10/100 •_Gigabit Ethernet supported via PCI Express •_ATI provides increased flexibility for partners •_Choice of provider •_Cost savings for implementation •_Leading edge technology •_Best of breed partners ensure ATI can deliver the latest and fastest networking solutions on the market today (Marvell & Broadcom) •_Integrated GbE offers no performance or cost advantage different anti-aliasing patterns within each frame. ATI Radeon X850 XT

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The ATi Cross Fire solution we'll be testing today consists of the following three main components, an ATi CrossFire Edition "master" Radeon X850 XT card, an ATi Radeon Xpress 200 CrossFire Edition chipset based reference design motherboard, and a second ATi Radeon X850 XT standard graphics card.  We've actually covered all of these platform technologies in previous HotHardware articles and invite you to scan through them now for a quick refresher course.

• Radeon X850 XT Platinum Edition
• ATI Radeon Xpress 200 Chipset Preview
• ATI Crossfire Multi-GPU Technology Preview

So again, the current requirements for a CrossFire setup are, as with NVIDIA's SLI, a completely proprietary solution.  That is to say, today you need a Radeon Xpress 200 CrossFire Edition board if you want to run a pair of ATi cards in CrossFire mode.  We have however, also confirmed that ATi will support Intel's i955X chipset for CrossFire eventually and have even heard rumblings from a few folks that nForce 4 support could be on the way as well, but for now and for what we have to work with today it's all ATi.  Certainly there are no limitations in hardware, with the PCI Express implementations that are found with any of these chipsets, but cross-platform characterization and compatibility in this area is a major undertaking.  Without question, if ATi can pull this off, it will obviously expand the market opportunity for CrossFire significantly and certainly allow them to take on NVIDIA with a bit more punch.