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Sapphire Pure Crossfire A9RD480 There was something we meant to say .. but we forgot
(Review by MS, Dec 22 2005)

As one of ATI's major OEM partners, Sapphire is finally moving into the motherboard scene and, naturally, Sapphire is also amongst the first to come out with a Crossfire edition motherboard based on the ATI Halibut design. On paper, the board looks great, the quality of components is stellar, and the color scheme of the board - along with an excellent layout - make the Pure Crossfire (PC-A9RD480) look like a dream come true. Behind the surface, though, there are still some issues, some relating to drivers, some relating to compatibility, and last not least, maybe some issues with the specific board we had for testing. After several weeks of looking at about every possible angle of the Pure Crossfire, we weeded out a bunch of bugs, found some mis-documentations and some workarounds for quite a few problems.

Are we happy now? To be true, there is no way of answering that question in a single paragraph, in fact, we have some 18 pages, for your reading pleasure...

For at least a decade, the Intel-centric world has been dominated by centralized processing in the form of software emulation relying on CPU cycles instead of dedicated hardware. The world of graphics adapters never really conformed to this recipe, after all, graphics processors cover a much more restricted spectrum of executions but within the predefined range, they are orders of magnitude more powerful than any contemporary CPU. The evolution of graphics, therefore, went hand in hand with the evolution of video processors to be replaced by graphics processing units and finally visual processing units that dwarfed any CPU with respect to their complexity, transistor count, programmability and last not least die size.

Associated with the above Darwinism was necessarily the increase in power consumption, concomitant with a linear increase in thermal dissipation. Needless to say that replacing the raw biomass of one single T-Rex with the equivalent in the form of a bunch of smart rodents has been a very successful strategy for millions of years - hence, to no big surprise, even the hardware designers have finally grasped the concept. The result is a moving away from the centralized towards a distributed computing approach, in this specific case, a multi-GPU solution.

Sneak preview of things to come

Multi-GPU configurations are nothing new, starting with the ATI's Rage Fury Maxx, 3dfx Voodoo2 and later Voodoo5, or Quantum3D's solutions featuring up to 16 discreet graphics processors, the idea has been around for almost a decade in all sorts of variations, from a tiled approach to the infamous SLI as in Scan Line Interleaving and Alternate Frame Rendering (AFR). New to the batch are the load-balanced Split Frame Rendering (SFR) as one of the options in nVidia's revamped SLI, short for Scalable Link Interface and ATI's SuperTiling (ST) as the preferred load distribution of the Crossfire platform.

In short, SFR is somewhat of a double-edged sword with limited returns compared to the AFR approach. SuperTiling on the other hand splits each frame into a checkerboard pattern of 32x32 pixels that are rendered by either the master or the "politically incorrect" slave card. On the surface, ST may appear somewhat clumsy and prone to imbalances in the load distribution, however, statistically, the tiles are small enough so that in real life, this issue should never become a predominant problem. In addition, the integration of SuperTiling seems straight forward, after all, there is no complex interaction between the two cards required.