Consider a dual-GPU graphics card like the Nvidia 590 or the Radeon 6990.
Does anyone know if such a card cwill show up as a single or two devices? If just one device, has the device automatically access to all compute units on the card, or only to one internal GPU?

Does anyone know if this is also platform-dependent (diff between Nvidia and ATI/AMD; some stuff having to do with cross-fire / SLI etc?)?

thanks !