Integrated + discrete in SLI
It seems like Nvidia has decided to expand its SLI technology to involve integrated graphics as well as discrete cards and a combination of the two will be possible when the next generation of integrated graphics parts arrive from Nvidia.
It seems like the idea of the technology is slightly different from normal SLI, as it allows for the discrete cards to be shut off when they're not needed and the integrated graphics part taking over.
This makes sense for mobile usage and it is similar to AMD's recently announced PowerXPress technology. But judging by the information from Nvidia so far, it might even make an appearance on desktop systems.
"Depending on the processing demands of each application, the discrete GPU may be completely shut-down to save power. For the most powerful of systems, where the combined power of dual Geforce 8800 GTX SLI can reach 400W, both GPUs can be powered down when the user is just doing email, surfing the web, or watching a Blu-ray movie, keeping the system completely quiet and consuming the least possible energy."
That doesn't look like notebook talk to us, but it doesn't rule out any specific platform. It will most likely appear on the upcoming MCP78 and MCP79 DX10 parts first, but there are no limitations to what platforms this technology will work on in the future.
It's always nice to get some extra performance and if you can take advantage of that integrated graphics core even after you've attached a graphics card to your system, why not?