“A New and Improved Moore’s Law: Under “Koomey’s law,” it’s efficiency, not power, that doubles every year and a half or so”
"Researchers have, for the first time, shown that the energy efficiency of computers doubles roughly every 18 months.
The conclusion, backed up by six decades of data, mirrors Moore’s law, the observation from Intel founder Gordon Moore that computer processing power doubles about every 18 months. But the power-consumption trend might have even greater relevance than Moore’s law as battery-powered devices—phones, tablets, and sensors—proliferate.”
The reference for the actual article is below.
Koomey, Jonathan G., Stephen Berard, Marla Sanchez, and Henry Wong. 2011. “Implications of Historical Trends in The Electrical Efficiency of Computing.” IEEE Annals of the History of Computing. vol. 33, no. 3. July-September. pp. 46-54. <http://doi.ieeecomputersociety.org/10.1109/MAHC.2010.28>
Subscription is required but I can send a pre-pub version if you email me.
You can see the key graph here (there is also a link to a talk I gave at Microsoft on the topic in December of last year): http://www.koomey.com/post/2678649528
Finally, here’s the abstract of our article:
This article describes long-term trends in the electrical efficiency of computation that enabled the creation of laptops and other mobile computing devices. If these trends continue (and we have every reason to believe that they will) they presage continued rapid improvements in battery powered computers, sensors, and controls.
The electrical efficiency of computation (measured in computations per kilowatt-hour, or kWh) grew about as fast as performance for desktop computers starting in 1975, doubling every 1.5 years, a pace of change comparable to that from 1946 to the present. Computations per kWh grew even more rapidly during the vacuum tube computing era and during the transition from tubes to transistors but more slowly during the era of discrete transistors. In 1985, Richard Feynman identified a factor of one hundred billion (1011) possible theoretical improvement in the electricity used per computation. Since that time computations per kWh have increased by less than five orders of magnitude, leaving significant headroom for continued improvements.