ATI has said that their next line of drivers
are going to include not only support for dual GPUs, but also code to take advantage of dual core processors. Although it seems that it would be the software of the game, perhaps the OS, to handle load balancing between CPUs or cores, but in a way it also makes sense. nVidia cards already do this to a degree, but this would be a new design, allowing the cards to offload whatever work they wanted to the CPU if it would be more efficient. Both ATI and nVidia claim this could bring performance boosts of up to 30%. Though I see that happening with current games, I don't think that would happen when true multi threaded games start hitting the shelves.