Tiny Smarfones, huge procesors?

ScotLudo

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Feb 13, 2013
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10,510
Hi Tom, my first question on your site tho' I've lurked many years.Ihave a question about processors and cooling. Today, my daughter took delivery of a "smartphone" boasting a 3 core proccessor. This device is as as thin as my wallet on payday -1, and cooler than the ex's passion even a good day. Now, I am writing this letter on my worakday machine, which I have tried to make as quiet as possible, eg by installing ssd drives,rewiring my home with Cat5E cabling, and and banishing all regular "spinning" hard drives to NAS in another room. All OK. bar the fan! My workday machine also boasts a 3 core proccessor, but needs a cooing fan the size of a house brick. Why is this Tom?
 

ChilledGrease

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Dec 22, 2012
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More cores and bigger doesn't mean faster or more powerful. Even though they have the same number of cores, the architecture of the processor and the clock speed is vastly different. Your computer's processor (Assuming it is a few years old or less) is vastly more powerful than your phone's, and because it runs at a much higher clock rate (roughly 3GHz vs the 1GHz of the phone), it uses ALOT more power, which generates a lot of heat. Your smartphone's processor is designed to be extremely power-efficient, thus releasing less heat. Also, the size of your phone's processor is much, much smaller than your computer's, because it is designed for a phone. Because it is so much smaller, it has less transistors of a very different architecture, thus making it a lot less powerful than your computer.
 
Processors in Smartphones and tablet are designed to use very little power. Those two market segments are dominated by ARM processors. To put it in layman's terms, they are simpler in design than desktop CPUs. Which partially explains why they consume very little power. As a result of a "simpler design", they are also much less powerful than a desktop CPU. So less powerful, but probably capable of sipping around 3w - 5w (just a guess).

Desktop CPUs are more complex in design. They have much more transistors than an ARM processor. More transistors means more power consumption. The trade off is that they are vastly more powerful. The Cortex A9-ARM CPU (the most powerful ARM) has around 26 million transistors An Ivy Bridge CPU has approximately 1.4 billion transistors.

So how powerful is a Cortex A9 ARM processor vs a Core i7-3770k CPU? I really don't know, but I will have to say that the Cortex A9 would likely be less powerful than a Pentium III CPU. Can a Pentium III CPU playback movie files encoded using the X.264 codec? Hell no. But then again it also does not have hardware specifically designed to aid in the decoding of something so complex.

CPUs will consume less power over time, but don't expect a desktop CPU to use 3w- 5w of power. In a desktop power consumption is not too much of a concern since it is always plugged in. For a laptop, that is a different story. And for tablets it is even more important. Intel is taking steps to reduce the amount of power their CPUs are using. But it will be sometime before their mobile CPUs can sip as little power as ARM processors. Then again desktop / laptop CPU have immensely more processing power.

The Haswell CPU series is Intel's real step to lower power CPUs. And low power versions using 13w or less should make it into tablets capable of running Windows 8. It will be several years before Intel can produce a low power CPU for smartphones. They started working on it last year; can't remember the codename for it, but it is expected to have up to 48 cores and Intel estimates they are 5 - 10 years away from a commercial product.
 

twelve25

Distinguished


You are comparing apples to hamburgers here. Think about the performance difference of the two systems.

 

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