Re: GTX 470 Sli
Do Nvidia drivers now let the user allocate 2 GPUs to rendering graphics and 1 to PhysX? The main reason why I never went with triple-sli is that the NV drivers wouldn't let the user dedicate one of the 3 cards to Physx. It's why I went with 2x280GTX or 2x295 + 1 9800GT for Physx instead. In Physx games, 2 GPUs in SLI plus one for PhysX is always faster than 3 GPUs in SLI (assuming they're from the same class).
I think that's why Just Cause 2's performance is somewhat disappointing even on a 480GTX. The developer's choice to use CUDA instead of Physx meant that the water effects can't be offloaded to a GPU that was just dedicated to physics calculations.