While ATI Technologies does not currently officially support any technologies that could enable multi-GPU graphics sub-systems on desktops or workstations, a recently released plan from Alienware is likely to provide users of ATI’s RADEON products to use them in pairs to gain additional performance, similarly to NVIDIA’s SLI technology.
Alienware, a leading manufacturer of high-performance computer systems, announced a licensing program for X2, a proprietary and patent pending technology for including multiple PCI Express x16 expansion slots on a single mainboard. This license is being offered through Alienware Labs Corporation, the research and development arm of Alienware Corporation.
Alienware’s dual graphics cards option will not require driver support from the graphics card manufacturers. The system was designed to be standalone using Alienware’s Video Array (including software and merger hub) and X2 mainboard. Video Array Technology divides the screen in multiple parts, in contrast to 3dfx’s SLI that required every single line to be rendered by different graphics card. In the case of using two video cards, the screen is divided, vertically, in two parts: one video card renders the upper section, and the second video card renders the lower section.
Video Array uses a ‘Predictive Load Balancing’ technology that evaluates on each frame the processing load for each GPU. Based on this, it ‘predicts’ the load distribution for the next frames, and adjusts the ‘Split Ratio’ accordingly. While the system always starts at a 50% split, as the content of the screen changes, the ratio changes accordingly (75%/25%, 85%/15%, 80%/20%, etc., etc). This logic enables Video Array to maximize the use of the graphics processing power from each card.
The X2 and Video Array still require a chipset that may support a number of PCI Express slots, such as Intel’s E7525 and NVIDIA nForce4.
Preliminary testing of dual graphics cards shows performance gains of more than 50% compared to single graphics card configuration. The more graphics intense the application, the more performance increase gained.
NVIDIA Corp. also offers a technology that allows two graphics cards to work in parallel to deliver additional speed. While NVIDIA’s approach is commercially available now, Alienware’s technology allows to install both NVIDIA- and ATI-based graphics cards.