Wax Coated Smart Phone Processors - Sizzling Cool User Experience

Microprocessor based consumer systems are mostly designed for continuous performance. In the case of mobile phones and tablets it is quite often that these processors are required to deliver sporadic fast bursty performance to achieve better responsiveness. This short computational burst is what is termed as computational sprinting- all processor cores performing intense parallel computation for sub second durations. All otherwise powered down cores (dark silicon) are active during this sprint.

Taking a processor from jogging to sprinting, so to say, entails over-coming a number of challenges. One of the rather obvious ones is to take the excessive heat generated during sprints away from the processors as quickly as possible. This allows the processor to keep on super-performing at high speeds without getting smoked.

One interesting technique to keep the processor cool while sprinting is coating the processor with wax. This has recently been experimented with at the University of Michigan. At higher temperatures, wax begins to melt. This change of phase from solid to liquid takes place at a constant temperature and as such the temperature does not go beyond the wax melting point. Before all the wax turns into liquid, the processor goes back to its normal jogging pace, giving sufficient time to wax to turn to solid before sprinting again.

This slow-fast or jogging- sprinting cycle can be made to repeat itself as many times as required within the limits of stability.

Presently the power boost so achieved in an Intel i7 processor during the sprinting state is five folds, from 10 Watts to 50 Watts. Researchers at UoM think they can take this up to a 100 Watts.

Besides cooling there are other issues related to sprinting such as taking high power (high current) from the battery to the processor, etc. These issues need to be resolved before we can really see this wax making our phones and tablets so wonderfully responsive.