By now we can safely say that 400 million dollars later, the G80 architecture was good to Nvidia. First released in November 2006 in the form of the still quite capable GeForce 8800 GTX, this then new graphics architecture set an industry benchmark that was not met by ATI until very recently.
If the Radeon HD 3870 X2 is essentially two Radeon HD 3870 GPUs put together on the same PCB, then it is safe to say that the new GeForce 9800 GX2 is no different, with two GeForce 8800 GTS 512 GPUs slapped together on a single PCB.
What ATI should find scary about this is that the GeForce 8800 GTS 512 is significantly faster than the Radeon HD 3870, and so that gives us a good starting point to start analyzing the GeForce 9800 GX2...