# [Q] Slow vs faster clock speed with same voltage

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By toebee76, Senior Member on 27th May 2014, 03:52 AM
So I looked around but couldn't find an answer to my question. I'm sure it must have been asked somewhere but I couldn't find it. I would like to know if two different clock speeds with the same voltage use the same amount of energy. My g2 kernel goes as low as 300mhz but in my voltage testing the lowest voltage it can handle is 675mv. However I found that I can use that same voltage at 422mhz and still be stable. Would they both consume the same amount of energy? I've noticed cpu usage is slightly higher at 300 vs 422. I'm guessing that is because it takes longer to process. Does the cpu usage play into the energy used? Or does it still use the same amount of energy and it just takes longer to complete the process. Is there a formula to figure out which is best? Thanks for reading!

27th May 2014, 05:24 AM |#2
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Originally Posted by toebee76

So I looked around but couldn't find an answer to my question. I'm sure it must have been asked somewhere but I couldn't find it. I would like to know if two different clock speeds with the same voltage use the same amount of energy. My g2 kernel goes as low as 300mhz but in my voltage testing the lowest voltage it can handle is 675mv. However I found that I can use that same voltage at 422mhz and still be stable. Would they both consume the same amount of energy? I've noticed cpu usage is slightly higher at 300 vs 422. I'm guessing that is because it takes longer to process. Does the cpu usage play into the energy used? Or does it still use the same amount of energy and it just takes longer to complete the process. Is there a formula to figure out which is best? Thanks for reading!

Good question. I believe it also depends on the architecture that whether consume same amount of energy or different. The concept of clocks is physics. Clock speed determines number of spikes in a cycle of voltage. In other words they are introduced to bring the processing faster. Everyone wants speed but better battery life. So what they will do is increase clock speed to handle more information in the same cycle and there by using same energy. This is theoretical. But practically more the clock speed more efficient the CPU/Architecture need to be , to handle things effectively at the same energy consumption. Otherwise it may consume more. This is what I think. Let me also have a search. If I find out anything else, will let you know
28th May 2014, 03:44 AM |#3
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Thanks for the input. I guess another way to look at my question would be does the cpu use whatever the set voltage no matter the usage? Does 300mhz use 675mv no matter what the cpu usage is? If that is true then it would be better for my phone to run at 422mhz since the voltage being used is the same.
28th May 2014, 05:07 AM |#4
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Originally Posted by toebee76

Thanks for the input. I guess another way to look at my question would be does the cpu use whatever the set voltage no matter the usage? Does 300mhz use 675mv no matter what the cpu usage is? If that is true then it would be better for my phone to run at 422mhz since the voltage being used is the same.

CPU will use the same voltage in both cases. But it doesn't mean it will consume same energy in both cases. I am not quite sure where It depends, may be on the architecture I guess. By the by I m just saying things I know. Didn't get any spare time to search for more information.

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