Assuming this is true, what would bring about this major change between the sheevaplug and the guruplug?
Ideally 205 mW extra for the sata port (worst case 410 mW if both are on). The extra NIC probably means an extra 700 mW (when loaded, but we have to assume the worst). Wifi/bluetooth is probably adds a few hundred mW too. So 1W of extra power isn't unlikely.
My *guess* is that the SoC runs at 1.7W in the sheevaplug, the memory probably contributes in the order of 1.5W, again a guess based on some random DDR2 datasheet i checked.
It's not unlikely that the sheevaplug heated up too, but how did it avoid getting warm/hot at the network plug?
EDIT: I now notice that the sheevaplug was stacked differently, the daughter board is between the main one and the psu, while for the guruplug the psu is next to the main board.