Robert X. Cringely on why Moore's law might extend for another 15 years.

This extra chip heat comes generally from four sources. The first is simply reduced surface area; yes the voltage is lower, but if the ratio of old voltage to new voltage is less than the ratio of old surface area to new surface area from the previous product generation and manufacturing process, well then the chip simply has to get hotter, since it is dramatically smaller yet doing the same work. Voltages drop linearly while surface areas decrease as a far more rapid square function.

The second reason chips -- especially microprocessors -- are getting hotter is the demands of keeping various clocks in sync. Using synchronous logic, some significant percentage of transistors is required simply to keep all the clock signals aligned on a 400 million transistor chip. Asynchronous -- clockless -- logic can do away with the need for that extra, power-wasting circuitry, as I wrote about in this space many years ago (it's in this week's links). As such companies including Sun and Intel are trying to make more and more of their chip circuitry asynchronous, but that is a long and crooked path toward chips that consume no power at all in the milliseconds they aren't being used.

But the greatest producers of heat are relatively new on the scene: two forms of current leakage that are especially prevalent at feature sizes substantially below 100 nanometers. The smaller we go the tougher it gets.

The first type of current leakage is called "gate leakage," which is a quantum effect in which electrons mysteriously migrate through materials they aren't supposed to be migrating through. Gate leakage is active, meaning it takes place only when the chip is actually running. Any leakage consumes power and creates heat without doing usable work, so of course we hate it unless, like I did with my old PDP-8, you are relying on your computer to heat your house.