ATI CrossFire – RADEON X800, RADEON X850 Ease the Burden for Each Other
ATI’s CrossFire technology currently allows to use two RADEON X800 or X850 graphics cards on a special mainboard in parallel to either boost performance or produce higher image quality.
ATI Uses External Interconnection for Multi-GPU
ATI does not seem to have any special logic inside its RADEON X8 graphics processors to allow multi-GPU solutions, but uses a special Compositing Engine to blend parts of images rendered by different graphics cards and external interconnection between the boards.
In order to set the CrossFire work, users will need one RADEON X800 or X850 card and a RADEON X800 or X850 CrossFire Edition graphics card equipped with Compositing Engine. DVI-I output of a typical graphics card should be connected to DMS port of CrossFire Edition card using a special cable provided with CrossFire Edition graphics cards. The CrossFire reportedly does not transfer data between graphics cards using PCI Express bus, even though initially the company planned to use this ability.
Currently CrossFire can only be enabled on a mainboard powered by ATI’s RADEON XPRESS 200 CrossFire Edition chipset, so, at this point CrossFire is not certified to work with NVIDIA nForce4 or Intel 945/955-series chipsets. While ATI does not have any special logic than enhances performance of two PCI Express graphics cards and, in theory, there is no difference for graphics cards which chipset is used, in practice ATI demands that a mainboard featuring RADEON XPRESS 200 CrossFire Edition chipset to be utilised.