I’ve just come across a paper from Intel published earlier this year that looks at the electrical efficiency of computation over time.
The paper explores the relationship between the performance of computers and the electricity needed to deliver that performance and comes to the conclusion that computations per kWh have been growing about as fast as performance. Growth was even more rapid during the vacuum tube computing era, but slowed as discrete transistors were introduced. However, since desktop computers made an entrance in 1981, computations per kWh have been doubling every 1.5 years, which is the average from 1946 to now.
What’s driving the improvement is the fact that smaller transistor sizes also tend to reduce power use, hence efficiency has increased with performance. If the trend continues, then the paper believes that there will be continuing rapid reductions in the size and power use of mobile computing devices.
Lets hope so. The proliferation of devices is likely to outstrip increased efficiency for a while yet and there’s not much we can do about that (except discourage people from using multiple devices, particularly in the workplace) but at least increased efficiency will help.