Why We Can Expect Ever More Amazing Mobile Computing Devices in the Years Ahead

This talk will explore the relationship between the performance of computers and the electricity needed to deliver that performance. Computations per kWh grew about as fast as performance for desktop computers starting in 1975, doubling every 1.5 years, a pace of change in computational efficiency 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. As expected, the transition from tubes to transistors shows a large jump in computations per kWh.

The main trend driving towards increased performance and reduced costs in the microprocessor era, namely smaller transistor size, also tends to reduce power use, which explains why the industry has been able to improve computational performance and electrical efficiency at similar rates. If these trends continue (and we have every reason to believe they will for at least the next five to ten years), this research points towards continuing rapid reductions in the size and power use of battery-powered mobile computers, allowing further rapid progress in mobile sensors, computing, and controls.

Speaker: Jonathan Koomey, Stanford University, Civil and Environmental Engineering