Multi-core Processor Power Efficiency Explained

Steve Smith talks about how processor core counts, die size and optimized programming can lead to more power efficient processors and task execution.

Episode #8-09 released on October 22, 2017

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This is a response to the question from Pirasutt Sriprayul, who asked does higher core count processors require more power than their lower core count counterparts?

I was asked an interesting question from a person who follows my Facebook page, does a processor with more cores take more power than a processor with fewer cores. Then I looked it up, and what I found out was amazing, but combine that with the die size of a processor and you might end up scratching your head on how it can possibly be true.

First thing I learned on this topic was that with older single core processors like the i486, Pentiums, etc. programmers relied heavily on the brute force of processing power of the core to make the programs run faster and faster. Efficiency, even with power requirements for the CPU itself was an afterthought, and something that was unsustainable. The Pentium M was the beginning of the end when it came to brute force power in favor of efficiency.

A math equation which you can see in the sources of this, indicates that everything being equal, a processor with two cores can be forty percent more efficient than a single core processor. And, when coded for correctly by programmers, the program can, also, be more efficient and faster, as well.

Well, then, there are, also, several other factors we forget about that would, also, explain, at least in an incredibly simplistic way, higher core count processors may be more power efficient than lower count processors, and this comes down to the nanometer size of the die used of the processing cores, as well. Electrons have a finite size, making the maze they must travel within smaller and smaller means fewer electrons are required to flood the maze. Fewer electrons means less power, more cores mean more efficient, better programming leads to faster reaction times of the programs users are using. And, faster more efficient coding requires less processing time, which, also, equates to a better power savings. Which, also, means fewer electrons required to cross the maze.

Which brings me to an important caveat, programmers can limit the number of cores their program can run on, so even if the processor has access to 8 cores, if a given program is hard coded to use no more than 4 cores, which power usage may be down, the overall efficiency may take a hint. In those cases, we often say that if you donít need dozens of cores, you are probably better off without them. After all, modern processors are far more power efficient than those from the original x86 and Pentium days.

Host : Steve Smith | Music : | Editor : Steve Smith | Producer : Zed Axis Dot Net

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