We've got our hands on a page of a presentation about three-way SLI and it looks like it won't have as much to bring to the table as normal SLI does in terms of performance increase.
As we don't know which benchmark or how it's represented in the graph below, it's hard to draw any real conclusions apart from the fact that it'll be faster, which is a good thing.
If our interpretation of the graph is correct, then three-way SLI should offer better performance per card than SLI using two cards. We're not sure how Nvidia has managed to pull this one off, nor if this is the case in all scenarios.
It doesn't seem to add a full cards performance, but if you compare the size of the graphs you'll notice that the third card adds a bigger bit to the graph than a second card seem to do.
Have a look at the picture and draw your own conclusion. What we'd like to know is what happend to the whole in-game physics thing, Nvidia? AMD?