Smartphones and dark silicon
If you like to keep up to date with science or, for that matter, if you enjoy science fiction, you will be no stranger to the concepts of dark matter and dark energy. Dark matter is the invisible matter that is believed to keep the bodies that form the galaxies bound together and to stop them from flying apart, and dark energy is the energy is a kind of negative gravity that is believed to be responsible for the universe to keep expanding at an ever increasing rate. But it seems that the next generation of smartphones will rely on another concept that is known as dark silicon.
With the Samsung Galaxy S3 about to be launched, and everybody eagerly awaiting the chance to sign up for Samsung Galaxy S3 deals, there is still a degree of speculation regarding the phone’s specifications. Not long ago the Samsung Galaxy S2 with its twin 1.2 GHz microprocessor was the talk of the town, especially as it was significantly more powerful in terms of computing power than the Apple iPhone 4S, but then out of the blue appeared the HTC One X, with a quad core 1.5 GHz microprocessor. In fact if you delve a little deeper the One X has five cores, one of them being a relatively low power core that consumes very little battery power and which takes over the operation of the phone when the fast cores are not required, for instance when playing music over Bluetooth.
In all likelihood the Galaxy S3 will sport a very similar processor to the One X in that it will be a quad core 1.5 GHz device, but how much further can these guys go? It seems that smartphone microprocessor technology has been pushed as far as it can go, particularly as the faster the phone the shorter the battery life.
But, enter stage right,” Dark Silicon”. Far from being villainous, dark silicon could be just the thing to make our smartphones go even faster. There is no fundamental problem in making microprocessors that can work at 10 GHz or even faster; they are pushing the limits of current technology, but they can be produced. The difficulty is that they use a great deal of electrical energy and dissipate a lot of heat. If you put one in a mobile phone, the phone would literally melt and you battery would catch fire.
It has been proposed that dark silicon can overcome this problem. The concept of dark silicon involves leaving much of the microprocessor unused until it is actually needed. Software determines which parts of the chip are needed for any particular application, and all the other parts are switched off. This means that the parts that are working can work very much faster without wasting any battery power or creating extra heat.
For much of the time a mobile phone is performing only basic applications and doesn’t need super-fast computing power. It is only when using certain applications and multitasking that powerful computing is required. It has been suggested that using dark silicon could extend the battery life in a modern smartphone by an order of magnitude or more.
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