It's amazing how little has actually changed with the internal design of the console, obviously some components have changed (e.g. DRAM) but the general layout remains the same after two years.

Here's what's interesting: the CPU, GPU and eDRAM die all seem to have gotten smaller, but at different rates. The CPU sees the biggest reduction in size, the new core being about 75% the size of the old one, while both GPU components are around 85% the size of their predecessors.
It's possible that all three chips are now 65nm, or a mixture of 65nm and 80nm (TSMC's 80nm half-node process was used in ATI's R600 GPU). Needless to say, the chips are all smaller, which should yield some nice power savings.

The power savings of the new Xbox are dramatic:

Playing Halo 3 on the new Falcon consumes less power than the old Xbox 360 just sitting idle at the dashboard.

http://www.anandtech.com/gadgets/sho...spx?i=3152&p=1