Looks like the new CPU+GPU Arrandale will not have what t takes to compete with Intel's latest ultra-low voltage CPUs.
According to an article at Fudzilla the new 32nm+45nm dual chip package will have a 35W TDP. Now this does represent a savings over traditional setups. This can allow for smaller, thinner and lighter notebooks.
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The official number is 35W for the dual core 32nm CPU and its 45nm IGP graphics. This is far from being cool but its not that bad either. At the same time, the Calpella two chip platform will offer a 38 percent area saving over the Montevina platform, which probably means that notebooks could become smaller and thinner.
To paint a better picture, a T9400 Core 2 Duo at 2.54GHz has the same 35W TDP, while T9600 at 2.66GHz can maintain 25W TDP.
The GM45 consumes 12W which gets the whole notebook platform to 47W before we add the TDP values of the Southbridge that is at least additional 5W. Arrandale will get things better as the whole CPU and graphics will get you to 35W TDP, but Intel's ultra low voltage CPUs can have a TDP of 10W and Arrandale cannot really compete with that.