Undervolting - Nexus 5 Q&A, Help & Troubleshooting

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
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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.

Related

[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] Underclock - usefulness AND values

I am playing a bit with underclocking my DS (Using UNITY v4 kernel atm, will update to v9 later).
However, I'm figuring out the usefulness of it (to extend battery life mainly).
Does it really save battery life? I'm already using JuiceDefender, and its SetCPU function.
Or is it not very useful since the most batterydrain comes from radios anyway.
What are the best values for it?
What's the standard clockspeed for the DS? And what is the best Max IDLE clock speed?
Well, i wont underclock at all.
First of all there is no need to do that to get good battery life. You can do lot other stuff to do so.
Under-clocking is risky as it might now have enough power that needed to the phone. that means that some stuff might not get processed like calls and stuff.
Right now with me using miui i get life for about 3-4 days.
Standard clock speed is 1,000mhz.
I have mine underclocked to 600mhz during idle times and it's perfectly fine.
Never had any issues at that speed and it keeps my Desire S much much cooler which can only be a good thing.
As for it's ability to extend the battery, I don't think it does so much in my case. I typically run WiFi overnight and G/3G/H during the day and my display usually chews up 60-70% of my overall battery usage even on a very dark screen.
I'd pick a setting that you feel comfortable with but have low expectations of the benefits.
The only time I use underclocking is for using Google Navigation.
On a hot day using Navigation for over a couple of hours, my DS would over-heat and restart (usually as I was approaching my motorway exit). So I have Tasker dialing back CPU to 768Mhz when using Navigation, and it does seem to help the phone run a little cooler. I no longer have to take it out the case for example.
Using the smartass governor (I believe) automatically knocks the CPU back to 240Mhz when sleeping. Not 100% on that though.
I'm currently testing a new kernel, and I spent an entire charge cycle on 'Smartass' and then an entire charge cycle on 'Powersave'. Aside from lots of lag on the latter one, the battery life was pretty much the same!

Q)? Pyroice kernels

I saw. 3 kernel.
Slightly. Uv
Midle. Uv
Extremely. Uv
What are the differences. Between. Those. ????
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Saw that too - exciting!
UV is undervolt, which means running the device with less voltage (electricity). Uses less juice, battery lasts longer, and doesn't run as hot.
Depending on what you do with the device and how it's implemented the results could range from awesome battery savings without a reduction in performance to brownouts and having the processor work harder to get the same job done.
If you do a lot of processor intensive stuff ( resource heavy games, for example ) undervolting becomes a harder thing to take advantage of because the processor has to work harder when it gets maxed out.
The fact that tbalden lifted the artificially low 1.2 clock speed and bumped it up to it's rated 1.5 offsets that somewhat.
For most people undervolting is a godsend, because they don't miss that top % of maxed out processor performance.
Also, the greater range of speeds allows you to regulate the speeds of the device using apps (setcpu maybe) which can't set speeds outside of the range the kernel allows.
Tbalden got into what I was trying to before my crazy work schedule hit, and he is doing a whole lot for this device - now I'll be following the trail he's blazing instead of the other way around - win for the MT4GS community when people have time to make fun stuff like this for us to play with.
Haven't had the chance to read up on what he's done with it other then seeing it was there, so this is some general info to get you started with, there's a lot more to be said and I'm sure others will swing by and add to this description.
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Slight is slightly undervolted, meaning it saves less on battery
Middle is around 5% undervolted, meaning around 5% saving in battery drainage
Extremely is 8%
Depending on the quality of your cpu material, it can work on your CPU well, or if it is made of a silicium chip that is less clean then your CPU will say voltage is too low, and phone might reboot. So depending on your device it may or may not work out.
UVing the cpu means no performance decrease. You should find out which kernel is best for your device. Safe is to go from Slight to Middle and then to Extreme if the Middle works out well. If you have reboots, fall back this way: Extreme --> Middle --> Slight
Also, if you dont want to use the Overclock frequency range, use SetCPU or an alternative cpu tool to cap it to your like.
Thanks guy. Now I understad why my phone s batt last longer . I flashed the extremely kernel . And I'm using an anker batt. And adding profiles with set cpu
And I noticed. My battery. Last way longer then before . Even though. I set the main profile of the set cpu to 1.5 hz max. 1.0 hz min. Wich makes the phone run as. My loptop. . Thank u developers
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[Q] CPU voltage and Battery Life in using data

My experience of undervolting reflects what is widely said, as you undervolt more and more, the device becomes less and less stable, and the battery drain become more difficult to measure in battery monitor. The only plus side is that there is less heat produced.
I noticed that extreme undervolting (using least stable voltage possible on all clock speeds) does decrease battery drain, but only in certain circumstances. When i undervolt and underclock during gaming, the current comsumption decreases dramatically (40~60%) compared to standard voltages. However, when i try to use internet/data on wifi, 3g or 2g on undervolt+underclock, the opposite effect happens, and a lot more current is drawn and the battery life is dramatically reduced. This affects the standby time of the phone the most (even with no data). The theory is that because more power must be used (during radio data transmission and to maintain radio signal), less voltage means more current is drawn. However, other people have said that is not true. In phone calls however, undervolt/underclock doesn't seem to change the current drawn much.
Since I browse the internet on my phone all the time, my battery sucks when I undervolt. So I'm thinking that it's only better to undervolt if you have the phone on all the time only game all the time and have the phone in airplane mode.
I only have undervolted one phone, the HD2, but I would like to know what are you experiencing in terms of undervolting your phone? Do the things I said above happen on other devices?
i have u20i with custom kernel and rom, undervolted also, but it's stable
Just a little laggy on startup

Optimal Undervolt/OC Settings

So I have a few apps... Voltage Control, SetCPU, No-Frills CPU... but I've honestly been a bit weary to use them. I want the best battery life since I'm a heavy user, but I also don't want to overclock/set voltage to a point where I'll screw up my phone. I'll admit that I'm a novice user when it comes to voltage/overclocking, but not when it comes to ROMs, kernels, bootloaders, etc. I work with those all the time, but really trying to get the most out of the battery and CPU.
There's this thread I found that has someone's settings on it, but don't know if its good or how much this guy knows(no offense to him):
http://forum.xda-developers.com/showthread.php?t=1356211
Anyone got any insight or perhaps screenies of their optimally tested settings? VERY VERY appreciated to anyone that can help.
jgruberman said:
So I have a few apps... Voltage Control, SetCPU, No-Frills CPU... but I've honestly been a bit weary to use them. I want the best battery life since I'm a heavy user, but I also don't want to overclock/set voltage to a point where I'll screw up my phone. I'll admit that I'm a novice user when it comes to voltage/overclocking, but not when it comes to ROMs, kernels, bootloaders, etc. I work with those all the time, but really trying to get the most out of the battery and CPU.
There's this thread I found that has someone's settings on it, but don't know if its good or how much this guy knows(no offense to him):
http://forum.xda-developers.com/showthread.php?t=1356211
Anyone got any insight or perhaps screenies of their optimally tested settings? VERY VERY appreciated to anyone that can help.
Click to expand...
Click to collapse
there is no rule. every cpu is different. very different. my captivate took a lot of effort to get a meer 1300 mhz but my infuses get 1600 no problem at all. some infuses wont go to 1600 but more will go to 1500 than galaxy s's. they probably held out the best testing cpu's for the higher clocked phone.
for battery life try clocking @ 800 mhz and dont use screen off profiles just because it looks like a good idea to slow the cpu when you arent really using it(causes problems if the max freq is too low with some kernels) and test stability with your uv settings, go down a little at a time, for max frequency uv from the top down, for battery life go from the bottom up and disable the upper freqs if they become unstable. this is because rapid voltage changes can contribute to instability. too much differential will cause crashes if the uv is extreme or the oc is extreme.
at some point though the cpu settings will have a limited effect. the radios use battery as well. manage your screen brightness and try edge only with the screen off using any number of apps that manage the radio. try one of entropys kernels to avoid a feature of the wifi chip (or was it bt) from sucking power when in proximity of another device with the same chip. turn off sync if you dont need push emails from gmail or real time facebook updates and if you really need battery life get in the habit of togging wifi and bt and gps on and off depending on need. i do none on this because i always found the battery life adequate on samsung phones but on my aria, well it was a must and prolly why people hate android. htc and battery life dont go together unless you manually manage the phone functions.
That's a great bunch of information. I currently keep my Brightness at 0%, GPS off, Wifi only ON when I'm at work when the charger is plugged in.
I guess I'm more concerned with the undervolting than the overclocking. I'd rather preserve the battery life with undervolting... the overclocking isnt a HUGE concern, but it'd be nice to see. Regardless, if you have any "ideal" UV settings, or ones that have worked for YOUR Infuse(assuming you have one), then I'd love to see them.
at one point i had -200mv on every freq from 100-1600mhz and no crashes. i started manually editing the uv script (voltage control is only able to write -200 into the script unless you have the pay version) and forgot what i ended up with. but my first infuse was exceptional in that area. some infuses freeze above 1400 mhz no matter what voltage settings are used. about -50 seems to be safe 99% of the time with minor or no overclock across the board but you could probably go -50 down low and -100 from 400mhz up to 1200 and -50 or -75 on overclock freqs. with underclock or atleast no overclock it's probably safe to go -100 to -150. it may be safe to go much more than that as well but on a small number of phones that might be too far as it is. cpus are made on such a small scale that microns of inconsistency make large percentages of difference. many dont pass testing and qc. some are borderline for the application, some are exceptional. the smaller the architecture gets the more potential the design has for speed but the larger the variance in performance is given a manufacturing technique. obviously the manufacturing gets better and better combating this so that they can make smaller architectures they also have redundancy built in, but sometimes they just disable features of a chipset and market it as an economy version if they have a low pass rate. ever see a 3 core cpu for a pc? most are manufactured as 4 cores and on many motherboards the bios can unlock the 4th core with somewhat unpredictable results.
Again, some really great info for the technical guys such as myself. What is the best way to test the UV settings? The built in tools and stuff in SetCPU? Or is there another way that would be more effective and/or would get more realistic results?

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