Microsoft presented details about the new SoC that powers its latest Xbox 360 250GB consoles. Interestingly, this new 45nm chip integrated the CPU, GPU, memory controller and I/O into one big module. You can find more info at ARS Technica.
Produced on the IBM/GlobalFoundries 45nm process, it's fair to say that the new SoC (pictured above) is the first mass-market, desktop-class processor to combine a CPU, GPU, memory, and I/O logic onto a single piece of silicon. The goal of the consolidation was, of course, to lower the cost of making the console by reducing the number of different chips needed for the system, shrinking the motherboard, and reducing the number of expensive fans and heatsinks.
The SoC also makes the new Xbox design more power efficient, which is nice for consumers, but the real motivation behind boosting the console's efficiency is to reduce the size and cost of the power supply unit, and to realize the aforementioned savings on cooling apparatus.