From Moore’s to Koomey’s law

Wednesday, September 14th, 2011 by Roberto Saracco

You should take a look at this article published few days ago on Technology Review.

The Eniac computer, mentioned in the TR article was extremely power hungry

It doesn’t really say anything new but it shows that as technology progresses the way we look at it and our way or gauging it changes.

Moore’s has set the pace to the electronic industry for almost 50 years akin it a must to be able to double the processing power (the density on a chip) every 18 months. However in these last 3 years the focus has shifted from processing power to energy efficiency.

On the one hand the processing power being delivered by mass market PC started to exceed the need and hence the perception of users. On the other hand the tremendous uptake of mobile devices has turned people’s attention to the battery and how long it can resist before having to be recharged. Recharging a battery is inconvenient and running out of juice is even worse.

Hence, manufacturers’ attention has turned to create low power chips to decrease the drain on the battery.

Because of the energy saving focus researchers have started to look into the energy consumption history and as reported in the article a professor at Stanford, Jonathan Koomey, has found out that the energy efficacy, measured in terms of number of processed instructions per second has also decreased, halved every 18 months.

Actually, this is not surprising, since the increase in the density in the chip leads to shorter paths and in turns requires less energy. Still, it is nice to notice that. But now it comes the interesting part.

As the focus has shifted on energy consumption and new architectures are created (like the multicore) we are going to see that whilst the Moore’s law may start to slow down, the Koomey’s law is likely to progress.

In the next few years the Moore’s law will keep its validity (with some slowing possibly) but in the next decade it will have to stop (that is using silicon, the adoption of carbon based chips can extend it further). The increased pressure to save energy so that we can continue to increase the performances of our handheld devices and multiply the number of devices off the mains will push researchers to keep the pace of the Koomey’s law as before they did with Moore’s.

An interesting twist bringing more value to the user. However, we should be aware that the overall consumption is likely to keep increasing since the Koomey’s observation (I prefer to call it this way) is about a fixed amount of processing power and we keep increasing the overall amount of it.


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