ATI Technologies, a leading graphics chip company, has unveiled another addition to its multi graphics chip CrossFire technology for consumers. The company proposes to use the third graphics processing unit (GPU) for physics calculations and claims that even its mainstream GPUs deliver better raw performance when compared to dedicated physics processing units (PPUs) from Ageia.

“The addition of physics to the CrossFire platform, and the continuing evolution of CrossFire is based directly on the feedback of hardcore gamers - CrossFire is not ATI's platform, it's gamers' platform,” said Godfrey Cheng, director of marketing, platform technologies, ATI Technologies, responsible for ATI's CrossFire strategy.

The GPU company plans to install not two, but three PCI Express slots for graphics card onto a single mainboard and assign the third graphics processor for physics. Or just two use the second graphics card for effects physics processing in games that use Havok FX physics engine, which is especially designed to calculate physics on shader model 3.0-compliant graphics processors. ATI’s approach allows so-called asymmetric implementation: graphics card for processing physics may be totally different from the GPU processing graphics, e.g., Radeon X1600 XT for physics and Radeon X1900 XTX for graphics.

According to ATI’s internal benchmarks, Ageia PhysX PPU (366MHz) can perform about half a million sphere-to-sphere collisions per second, whereas the Radeon X1600 XT (590MHz, 12 pixel shader processors) delivers over a million, meanwhile performance of Radeon X1900 XTX (650MHz, 48 pixel shader processors) reaches five million sphere-to-sphere collisions per second. While the synthetic benchmark numbers impress, game developers yet have to implement support for the Havok FX engine to take advantage of the theoretical power.

The Havok FX product is currently in early release to select developers and is expected to be available this summer.

Havok FX supports a new type of rigid-body object called a Debris Primitive. A Debris Primitive is a compact representation of a 3D collideable object that can be processed via Shader Model 3.0 (SM3.0) in a very efficient manner. Debris Primitives can be pre-modeled as part of a game’s static art content (e.g. custom/textured boulders, space junk, or collateral objects waiting for an explosive charge). Debris Primitives may also be generated on the fly during game play by the CPU, based on the direction and intensity of a force (e.g. brick and stone structure blown apart by a cannon blast). Once generated by the CPU, Debris Primitives can be dispatched fully to the GPU for physical simulation and final rendering – comprising a powerful blending of physics and state-of-the-art shading effects for particulate and large scale phenomenon.

Havok FX Debris Primitives can even interact with game-play critical objects, through an innovative approach that will provide the GPU with a one-way transfer of critical information that will allow Debris Primitives to respond to game play objects and large-scale world definitions. Havok FX Debris Primitives may be simulated in either OpenGL or DirectX. Havok will provide programming samples that illustrate interaction of Havok FX effects physics with Havok Complete game-play physics, to ensure that Physics Effects based on Havok FX deliver an immersive experience.