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[Q] Help setting up CPU tuner/SetCPU

1st July 2014, 02:45 PM   |  #1  
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Hello, my main purpose is to save battery. I want let the CPU act normally (stock) while the screen is ON, and i want to undervolt/underclock the CPU, while the screen is OFF and when i am on a phone call. I do not care about overclocking.
Is there any CPU tuner (or even SetCPU app) guide for nexus 5?
I really want to know the correct frequences to setup in order to avoid problems
I use stock ROM and stock kernel.
Thank you in advance.
1st July 2014, 03:32 PM   |  #2  
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There are no correct frequencies. Just play and find what's good. Remember though, the more you underclock, the longer it takes to undertake certain tasks so it can be a false economy.

My advice would be undervolt always and under clock never.

You cannot undervolt stock kernel

Read section 4.3 in my signature

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1st July 2014, 03:48 PM   |  #3  
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Quote:
Originally Posted by rootSU

There are no correct frequencies. Just play and find what's good. Remember though, the more you underclock, the longer it takes to undertake certain tasks so it can be a false economy.

My advice would be undervolt always and under clock never.

You cannot undervolt stock kernel

Read section 4.3 in my signature

Sent from my Nexus 5 using Tapatalk

Thank you for answering and thank you for the information! I have 1 question in order to clear some things out. What causes battery economy Underclock or undervolt?
1st July 2014, 03:50 PM   |  #4  
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Quote:
Originally Posted by Dmoustakas

Thank you for answering and thank you for the information! I have 1 question in order to clear some things out. What causes battery economy Underclock or undervolt?

Both have potential but really the best thing is deep sleep.

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1st July 2014, 04:06 PM   |  #5  
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Originally Posted by rootSU

Both have potential but really the best thing is deep sleep.

Sent from my Nexus 5 using Tapatalk

I already use greenify so i think it is the same thing with deep sleep. One last question, could underclock be false economy in my situations since i want it to work only when screen is off and only on active phone calls?
1st July 2014, 04:18 PM   |  #6  
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Quote:
Originally Posted by Dmoustakas

I already use greenify so i think it is the same thing with deep sleep. One last question, could underclock be false economy in my situations since i want it to work only when screen is off and only on active phone calls?

Screen off does not = deep sleep. In my opinion, it's best to let it do what it wants, however my kernel sets maxscreen off at 1100 MHz

Its all about clock cycles. The Stock kernel allows the CPU to run at approximately 23,000 MHz. Each MHz is a "Clock cycle" per second. So each second, you have 23,000 clock cycles. Now lets say (this is not a real value, but just humour me) that an e-mail Push takes 23,000 clock cycles. You can receive an email in 1 second. With me so far? So what if you underclock to 12,500MHz? It takes twice as long to push that same email to your phone. So now you have to work out, is 12,500MHz using more or less than half the power that 23,000MHz uses? If it is less than half, you *MAY* save some battery, but if it uses more than half, its a false economy because 2 seconds at 12,500 uses more power than 1 second at 23,000.

Does that make sense?

I've kept this basic for illustration purposes, so anyone reading, please don't make technical corrections, this is not meant to be exact or accurate
1st July 2014, 04:26 PM   |  #7  
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Originally Posted by rootSU

Screen off does not = deep sleep. In my opinion, it's best to let it do what it wants, however my kernel sets maxscreen off at 1100 MHz

Its all about clock cycles. The Stock kernel allows the CPU to run at approximately 23,000 MHz. Each MHz is a "Clock cycle" per second. So each second, you have 23,000 clock cycles. Now lets say (this is not a real value, but just humour me) that an e-mail Push takes 23,000 clock cycles. You can receive an email in 1 second. With me so far? So what if you underclock to 12,500MHz? It takes twice as long to push that same email to your phone. So now you have to work out, is 12,500MHz using more or less than half the power that 23,000MHz uses? If it is less than half, you *MAY* save some battery, but if it uses more than half, its a false economy because 2 seconds at 12,500 uses more power than 1 second at 23,000.

Does that make sense?

I've kept this basic for illustration purposes, so anyone reading, please don't make technical corrections, this is not meant to be exact or accurate

Great explanation, clearly logical thoughts. You really covered all my questions. Thank you very much! I think i am going to search for a kernel to tinker with undervolting!
Cheers and thanks again!
1st July 2014, 04:29 PM   |  #8  
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Quote:
Originally Posted by Dmoustakas

Great explanation, clearly logical thoughts. You really covered all my questions. Thank you very much! I think i am going to search for a kernel to tinker with undervolting!
Cheers and thanks again!

No probs. Take a nandroid backup before tinkering

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