[Q] Does underclocking your phone (w/ SetCpu) really improve battery life? - Android Software/Hacking General [Developers Only]

Surely it makes little difference on a processor with dynamic clk freq scaling?
Assuming its always clocking at its slowest during idle, which your phone is by default, then reducing the max clock speed during activity just extends the time its chugging away at max speed.
Only way to improve battery life is to reduce the amount of work you ask of your phone, not the speed at which it gets on with it.
For example, if my Desire has to process an image, it can either do that in 1ms at 1GHz, or 2ms at 500MHz, using the same amount of battery, no? At all other times its idling at the same 250MHz.
So the way forward is to reduce tasks, not underclock? And if anything the profile conditions in SetCpu are just one more thread.
Anyone actually noticed better battery performance from SetCpu?

I noticed bader Battery Life! So i dont use it anymore!

I don't think it will give you more battery life to reduce the cpu speed. more important i think is to watch the tasks that run on the background. some apps can drain you battery really fast. i just use advanced task killer and set it to kill apps when i turn my screen off, for me it helps more then lower the cpu speed.

Those apps drain battery by not letting the cpu idle, hence lowering max speed could improve battery life.
Sent from my HTC Magic using XDA App

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[Q] Optimum "LOW" setting for performance based overclocking

I am loving my Android experience so far coming from and iPhone 4. I am running LeeDroid and have been playing around a lot with SetCPU. At this time, I am not concerned about battery as of yet. I am asking this question in regard to optimal, blazing fast performance with minimal hiccups.
I have done Quadrant testing at various min/max CPU levels. I had excellent results at 1804 high 904 min. However I had to yank the battery after not being able to unlock the device.
For profiles, real basic, again I am not concerned about battery charge life ATM. I have it set to revert to stock performace (1036/245) if the battery temp reaches 100F.
With the screen locked, I have it set to 499/245. All of my settings are using the "ondemand".
I would like to know what an ideal minimum is for PERFORMANCE as well as ideal max (1804? Highest might not always be fastest?). I got amazing results with Quadrant full benchmark with settings of 1804/499. This also caused a lockup when trying to unlock the device though. Maybe because there was a conflict with my lockscreen max setting? I would think the app would put priority to the lock profile though.
Also, does this phone have a built in CPU temperature sensor that I could utilize with a CPU temp widget?
Thanks for reading my lengthy ramblings.
Ray
Not all Processors are created equal and therefore some can OC to 1900+ and some cant overclock at all. Most will be in between. Sounds like you are over doing it. I clock mine to about 1400 when charging. I have had it to 1700 without an issue at all, but I don't find a need to be faster then 1400. When screen is off I actually tell it to go to 250MHz. Sometimes its alittle slow to "wake". But it saves mucho battery. When just on battery I am running at about 1250. Been this way for about 3 weeks. Not an issue.
I have never had to yank my battery and quite frankly if I did I would never run it that high again. You are going to burn it up running it at that speed. Nothing over 1500 for extended periods. 1800+ for showing off maybe? But that's kinda dumb too.
I have not read about any built in temp thing so can't really answer that.
I don't know what kind of power hungry apps you guys are running, but I run mine underclocked to 906MHz. Snappy as ever.

[Q] Battery life in Overclocked Phone

How about battery life in Overclocked phones?
Depending on how its clocked, if your needs are speed and usability it lowers the battery life.
Though you can clock it moderate and set the "min" clock frequency down and save battery while its in your pocket.
benjamin336 said:
Depending on how its clocked, if your needs are speed and usability it lowers the battery life.
Though you can clock it moderate and set the "min" clock frequency down and save battery while its in your pocket.
Click to expand...
Click to collapse
benjamin336 is absolutely right. I've also found that you have to adjust the settings differently depending on the phone.
There are threads pertaining to adjusting voltages and clocking where people describe what combinations have worked best for them.
99% of the time if you're looking to overclock you're looking for performance meaning 99% of the time you are going to have crappier battery life.

Undervolting/Underclocking

So recently I've become too lazy to constantly charge my Captivate and began to experiment with undervolting/underclocking it. Has anyone found optimal voltage for battery life? I've currently got every step of 200mhz down 100 volts and underclocked to a max of 800mhz. I'm on Semaphore kernel 2.9.5sc.
freshlimes said:
So recently I've become too lazy to constantly charge my Captivate and began to experiment with undervolting/underclocking it. Has anyone found optimal voltage for battery life? I've currently got every step of 200mhz down 100 volts and underclocked to a max of 800mhz. I'm on Semaphore kernel 2.9.5sc.
Click to expand...
Click to collapse
There isn't a optimal setting as all phones act different. Testing is the best you can do.
which cpu governor are you running? that may have more effect than underclocking/undervolting on battery life.
user Stempox has a nice post on cpu governors here
http://forum.xda-developers.com/showthread.php?p=28647926
the screen on time and data/gps traffic, and apps that keep the phone awake, do more to effect power drain than other factors. so, if you manage those, and choose the governor that suits you preferences, then undervolting and underclocking aren't needed, IMHO.
you can tweak the governor settings with Semaphore manager, if you really want to do that too.
the thing is, you may end up keeping the screen on longer than you would at higher cpu speeds, which would counter any battery savings. also, undervolting can increase the error rate, which means further delays while phone is awake.
hope this is helpful in your pursuit of fewer charging cycles.
Sent from my SGH-I897

An App to see what apps cause high CPU usage?

I know about cpuspy, better battery stats and apps like it. They allow you to see how long your cpu has been running at different speeds. My question is there any app that tells you exactly what App/process cause the cpu to go to a particular(highest speed). Getting really good battery life on the LG G2 and think I can make it better by using Per App Modes to tune down the CPU speed in apps that use the most power.

Undervolting

Hello guys
I'm not a new user in kernels or ROMs .
I have a low-decent battery life ,and I'm sure there's a way to get a better battery life with undervolting .
I want to know
what is "undervolting" ?
What is the biggest damage it can cause?
What is PVS?
How do I know ,how much I can UV?
What are the steps to undervolt?
What I gain from UV (despite battery life)?
For your info ,I'm using AOSPAL ROM +FAUX's latest 16u kernel .
Thanks
Sent from my Nexus 5 using XDA Premium 4 mobile app
http://forum.xda-developers.com/showthread.php?t=2537000
Sent from my Nexus 5 using Tapatalk
Hi,
Most of your questions have a reply:
About undervolting: http://forum.xda-developers.com/google-nexus-5/general/nexus-5-undervolting-thread-t2537000.
CPU binning: http://forum.xda-developers.com/google-nexus-5/general/cpu-binning-nexus-5-t2515593.
The "risks" are instability like hard reboot, SOD, etc.... To find a "safe" value you will need to test by yourself to find what undervolting your CPU can handle, not all CPU's are equals.
Undervolt by steps like - 25mV, don't set your new values at boot unless your are sure it's stable (or you could encounter bootloop), test for a few days under different conditions (as your use).
The gain apart battery life (but you will not gain that much as people tend to think) is a little less heat, but again nothing huge..., better is to test by yourself and see what you will gain... or not.
Battery life depends mainly of your use, apps, signal quality and settings like, screen brightness, synchro, CPU governor, etc... In my opinion check first what could be the cause of your low battery life (and what is low battery life for you???) before play with undervolting.
As said above, undervolting will get you very minor battery life increases.
More than likely you have an issue, or its just your setup and usage giving you the battery life you are seeing.
Undervolting will not change any of this.... You'll gain only minutes of battery time.
Try some troubleshooting in the below thread to see if you have an issue, or how to setup for better battery life. Read through it a bit, from the last page and work back a bit. You can post meaningful screenshots there too. From gsam or BBS.... not the stock battery screen, it has no real useful info for finding issues. Good luck!!
http://forum.xda-developers.com/showthread.php?t=2509132
Nexus 5 Battery Results
I've been undervolting many systems for many years, primarily Linux desktops and some servers, and the primary benefit is that you get less heat output which means when running cpu-intensive tasks the temperature climbs slower so the throttling of the clockspeed kicks in later, so your phone will be faster in certain situations. If you take a phone which has been idle for a while and run a benchmark, and then immediately run that benchmark again, the 2nd time gets a lower result as the phone is still hot from the 1st. This makes drawing conclusions about settings really dificult but it illustrate that throttling from heat is affecting speed.
For most users their perception will be the phone runs cooler.
You do undervolt at each step in the processor's frequency, and each step is a trial+error activity, the throttling I mention means finding a stable under-volt at the higher frequency which is labour-intensive,i.e take the max clock, and undervolt it a little, run a benchmark which forces it to run at high clockspeed, and if it passes that test then run it again at the next step down in frequency. Once you've got the most stable top clockspeed, then do it progressively for all the other voltages on the way down.
In some platforms in Linux and Windoze, we wrote scripts which save the stable voltages and then undervolts a little and runs a stress-testing benchmark and if the system hung it wouldn't save the current voltages so the previous higher voltages were safer, stick that script in a startup script area and leave the compute to do many self resets, and you've calculated your device's voltage range. I wonder if someone has that done for Android??? For a laptop the FAN would run slower saving battery time and for laptops that would lead to say 20% better battery life but on a phone it won't make much saving as no fan.
Your phone will run most of its time (like 95%) at its lowest frequency, so for effort/benefit just focusing on dropping its voltage will gain the most in the phone running cooler.
Battery life improvement is marginal, if you look at your battery stats its down to your application settings and screen brightness, i.e. how you use and what you do with your phone. So if your battery life is bad, use your phone less!
I carry a slim USB battery, it is the $/effort/benefit the best thing you can do, $20 doubles your battery life, if you get one with a 1.5A-2A output in just a few minutes when the phone doesn't mind a battery attached, will dwarth every possible tweak and hack anyone can form in benefit.

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