You saw a little of that with the 3870X2, but the bridge was a simple PCIe switch. The real magic this time is a bridge that shares memory, GDDR5 in this case. Yup, you will have 2 GPUs with one set of memory. This simplifies designs, lowers chip cost, and speeds time to market. You get two full variants for the design cost of 1.25, and you are on the happy end of the cost/area curve for fabbing silicon. While the early word on GT200 is that it is again 500mm^2+, ATI will have 2x chips that are much smaller, which translates into a huge cost advantage.