Last we heard, both AMD and Nvidia were prepping next-gen graphics processors for the fourth quarter of this year. The guys at Hardware-Infos now say Nvidia has taped out its upcoming G300 graphics chip, and they've posted some specifications for the product.
If the Google translation hasn't warped the post's meaning beyond recognition, Hardware-Infos says the G300 will have 512 stream processors, almost 2.5 teraFLOPS of number-crunching power, 1-2GB of memory, and 281.6GB/s of bandwidth. The memory will supposedly run at 1,100MHz, so assuming GDDR5, that would mean a 512-bit interface width.
As for the gigaFLOPS figure, the site goes on to say the G300's stream processors are no longer SIMD elements but "MIMD-like" (multiple-instruction, multiple-data) units. That could imply more complex, more flexible hardware, although the report doesn't talk about gaming performance.
With that said, a graphics processor with that much floating-point power and memory bandwidth probably isn't going to be small. And indeed, a previous post from the same source talks of a whopping 2.4 billion transistors—a billion more than the GT200.