R700 looks like an interesting chip, as it will change a lot of things. Nvidia currently talks about clusters, but most of these chips are blocks of functional units divided into these so-called clusters.
ATI will take a step forward and will introduce its mini core that will be one small part of a larger chip. ATI can use just one R700 core to get an entry level chip, two cores will make a mainstream card and four R700 cores should take care of the high end.
A single R700 core has just below 300 million transistors, and you can do the math: even four R700 cores means over a billion transistors and a lot of graphics processing power.