Database Users

Does under voting actually reduce battery usage?

Just wondering if the screen is the major battery draw like battery stats show or if the CPU uses the most and if under volting makes a difference.
Sent from my Nexus 7 using Tapatalk 2

maybe a little,
#1 battery drainer is screen brightness...

Personally I don't think so. Just my opinion tho I'm no expert.
Sent from my Nexus 4 using Tapatalk 2

The power dissipated by a chip is calculated by C*V²*f (V = voltage, f = frequency)
So undervolting will lower the power consumption a bit, but not much in comparison to the screen. Real life difference will be minimal.
Undervolting the 1.3Ghz step from 1.075v to 1v will theoretically lower the power consumption at that step by 15%. But the tablet spends most of its time in the lower cpu steps, where undervolting much is not that simple to accomplish. Don't expect huge differences.

no

I think it does a bit plus it reduces the heat a bit .
Sent from my Nexus 7 using xda premium

The big battery eater on the nexus7 is the screen, not the cpu. You will save way more juice by setting your screen to not be maximum brightness than you will by hacking up the kernel and undervolting.

Think I've read somewhere you may save 3% or so, the real saving is the reduction in temperature
Sent via TCP/IP

I can give a similar general consensus as the others. On smaller devices like my old evo 4G, Undervolting, especially at the lower end of the frequency chart, made a very noticeable improvement, but on a tablet device or device with a larger screen, the quantitative difference quickly dissipates. Undervolting may still help a decent bit in standby time (which I'd argue tablets spend in than phones) but screen on will make only a minimal change.

spankmaster said:
I can give a similar general consensus as the others. On smaller devices like my old evo 4G, Undervolting, especially at the lower end of the frequency chart, made a very noticeable improvement, but on a tablet device or device with a larger screen, the quantitative difference quickly dissipates. Undervolting may still help a decent bit in standby time (which I'd argue tablets spend in than phones) but screen on will make only a minimal change.
Click to expand...
Click to collapse
Actually there is no saving while in standby; the cpu goes into the deep sleep state which already uses very little power. While I can't say I've seen battery life improvements from undervolting, it sure keeps the device cooler.
Sent from my SGH-I777 using xda premium

CPU never goes above 1.440 ghz

So I usually use CPUSpy to monitor my CPU usage. This comes in handy once the device is rooted and I can see how custom kernels and settings affect battery life and cpu cycles. My LG G4 is the tmobile variant and obviously not currently rooted. I notice through CPUSpy that my cpu speed literally never exceeds 1440mhz.
I don't have any problems with that per say, everything on the device still runs buttery smooth without anything more than the occasional hiccup or lag. I'm curious if anyone else has monitored their CPU speeds and noticed the same thing? I just find it a little interesting.

CPU spy can't even see the A57 cores so there's no way it can see what speed it's running at.

4 cores are limited to 1.44 the rest are 1.8

I have not used CPUSpy. But CPU-Z will show you the speed of each of the 6 cores. As mentioned, the last 2 are the only ones I've seen reach 1.8GHz, the first 4 seem to top out at 1.4 GHz.

Ok.. Using cpu-z..

That's how mine looks "at rest". When it's sitting quietly, saving the battery. Crank up some apps, and you should see those clock speeds rise.
But, trying to improve my battery life, and keep the temps down, I've been hoping to see those numbers stay low, not actually show how high they can go

I agree.. As ive stated, the device runs great i just found it odd. It even calls it a 1.44ghz cpu in the cpu profile and mostly no matter how hard i push the device i cant break that speed

Right as CPU-Z opens, the clock speeds spiked briefly. I was able to get a screenshot quickly.
Do yours also jump up for a second or two right as the app opens?

This has been discussed already. As the previous post shows, they do get to 1.8Ghz when required.

Only 4 cores are used

Hello,
I have a peculiar problem with my OnePlus Two
The faster A57 cores don't get activated, I have tried using Antutu, played Asphalt 8 And NFS NL for hours.
But the cores just won't get triggered
I'm using A1 CPU tool to monitor the same.
Even CPU Z wouldn't show me any activity on the other 4 cores while Antutu was running.
Any ideas? It's brand new can be returned
Oxygen OS - 2.1.1
A2003_14_151011
Sent from my C6602 using XDA Free mobile app

Denhot said:
Hello,
I have a peculiar problem with my OnePlus Two
The faster A57 cores don't get activated, I have tried using Antutu, played Asphalt 8 And NFS NL for hours.
But the cores just won't get triggered
I'm using A1 CPU tool to monitor the same.
Even CPU Z wouldn't show me any activity on the other 4 cores while Antutu was running.
Any ideas? It's brand new can be returned
Oxygen OS - 2.1.1
A2003_14_151011
Sent from my C6602 using XDA Free mobile app
Click to expand...
Click to collapse
I just installed A1 CPU to verify your issue.
It shows cores 0,1,2,3,4 are used at 1344ghz for me as well.
When i check with synapse (i'm on AK kernel) it shows all cores are used.
I guess it's a limitation with A1 CPU tool. Try with other tool that supports such architecure.

I was sceptical on the same but, out of the box I remembered seeing 1777 MHz frequencies.
Thanks a lot
I shall try more tools and get back.
Though I think if you're on a different kernel and had the A1 CPU tool been correct it would be redundant, Because core allocation would be done on kernel level (in my knowledge).
Sent from my iPad using Tapatalk

I know that it was already discussed but maybe someone has found a solution.
The problem is that performance of device gradually decreases proportionally to the level of the battery.
For example:
- battery is 90%, Real Racing 3 runs perfectly,
- battery is 45%, some lags appear during gameplay
- battery is 10%, heavily FPS drop, almost impossible to play
Battery saver is turned off, device is cold in all tests.
If I would like to save my battery level - I will turn on battery saver manually,
but I WANT to have good game experience not depending on battery level
This is really crazy.
Tested on stock OOS 2.1.1, with stock kernel, with Boeffla an AK, tested on Exodus ROM - everywhere I can see this weird behaviour.
May be some system files must be edited to overcame this issue?

jemcik said:
I know that it was already discussed but maybe someone has found a solution.
The problem is that performance of device gradually decreases proportionally to the level of the battery.
For example:
- battery is 90%, Real Racing 3 runs perfectly,
- battery is 45%, some lags appear during gameplay
- battery is 10%, heavily FPS drop, almost impossible to play
Battery saver is turned off, device is cold in all tests.
If I would like to save my battery level - I will turn on battery saver manually,
but I WANT to have good game experience not depending on battery level
This is really crazy.
Tested on stock OOS 2.1.1, with stock kernel, with Boeffla an AK, tested on Exodus ROM - everywhere I can see this weird behaviour.
May be some system files must be edited to overcame this issue?
Click to expand...
Click to collapse
Hi Jemcik, hi Denhot!
I'm facing the same issues on my new device and it's definately not normal!
With a battery level of 19% I was not able to get the 4 A57 cores online, which results in lower system performance. Have you found a solution?
@Denhot!
Maybe we should rename the thread into: IS OPT PERFORMANCE REALLY DEPENDENT ON BATTERY STATUS AND IS IT A ROM FEATURE OR AN ISSUE!?
I think, one of the kernel devs should be able to answer this question.

ollimi1 said:
With a battery level of 19% I was not able to get the 4 A57 cores online...
Click to expand...
Click to collapse
It looks like some system configuration files with kernels activation policy have to be edited,
but I haven't found yet which files exactly.

jemcik said:
It looks like some system configuration files with kernels activation policy have to be edited,
but I haven't found yet which files exactly.
Click to expand...
Click to collapse
I've never experienced such a function!
CPU power depending on battery voltage!? 62k with full battery, 49k with 20% battery both with same CPU temps!
Hopefully not a general problem on our side with the motherboard Voltage Regulator or something.
Have you been to a kernel thread and asked this question? If not, I will ask this in AK's kernel thread. Maybe he knows more about it!

The 4 high performance cores will only be activated when needed. What app are you using to check the core usage? Every now and then you should see 2 of the high performance cores sometimes coming to life every now and then, with the other 4 power efficent cores being more busy. Use CPU-Z to check.
Due to the way Oxygen OS's stock kernel works, only 2 of the high performance cores will ever be active, alternating between the 4 cores in an attempt to keep the phone cool and not throttle as often. If you want all 4 high performance cores to be active as well as overclocking it back to its original speeds, you'll need to flash a custom kernel.

jemcik said:
I know that it was already discussed but maybe someone has found a solution.
The problem is that performance of device gradually decreases proportionally to the level of the battery.
For example:
- battery is 90%, Real Racing 3 runs perfectly,
- battery is 45%, some lags appear during gameplay
- battery is 10%, heavily FPS drop, almost impossible to play
Battery saver is turned off, device is cold in all tests.
If I would like to save my battery level - I will turn on battery saver manually,
but I WANT to have good game experience not depending on battery level
This is really crazy.
Tested on stock OOS 2.1.1, with stock kernel, with Boeffla an AK, tested on Exodus ROM - everywhere I can see this weird behaviour.
May be some system files must be edited to overcame this issue?
Click to expand...
Click to collapse
Hi,
would like to share I don't have a similar experience, with NFS NL or Asphalt, phone was consistent with no lags even when it got unbearable to hold.
I as playing and simultaneously screen mirroring over to a TV.
Going from 65 to 25% over a long course.
I normally won't let my battery fall below 20%.
So the thing about Li-ion/pro is that as you go lower voltage decreases so to provide same power draw current increases.
Basically it would heat up faster.
That can be a reason combined with that their might be inbuilt measures to save battery like you said, nor as an engineer I would recommend you to stress your phone at those levels.
I can't explain the lag at 45%, didn't find it might try real racing 3 later to check.
Sent from my iPad using Tapatalk

trapistasajt said:
The 4 high performance cores will only be activated when needed. What app are you using to check the core usage? Every now and then you should see 2 of the high performance cores sometimes coming to life every now and then, with the other 4 power efficent cores being more busy. Use CPU-Z to check.
Due to the way Oxygen OS's stock kernel works, only 2 of the high performance cores will ever be active, alternating between the 4 cores in an attempt to keep the phone cool and not throttle as often. If you want all 4 high performance cores to be active as well as overclocking it back to its original speeds, you'll need to flash a custom kernel.
Click to expand...
Click to collapse
This is consistent with what I've noticed. The time It didn't, a simple reboot helped solve it and it hasn't occurred since.
Also these tools can't monitor the other cores, if you're rooted why not try synapse as helkat suggested
Sent from my iPad using Tapatalk

Denhot said:
This is consistent with what I've noticed. The time It didn't, a simple reboot helped solve it and it hasn't occurred since.
Also these tools can't monitor the other cores, if you're rooted why not try synapse as helkat suggested
Sent from my iPad using Tapatalk[/QUOTE
Thanks man!
I know how the S810 should work!
But I thought the performance issues have only to do with the temps. But now it seems it have also to do with the battery level.
It would be good if someone tries to reproduce the following to verify it:
1. One run Antutu benchmark with fully charged battery and room cool temps.
To be sure the conditions are the same, shut the display off for one or two minutes, than start display again, kill all recent apps and run Antutu test and note the results.
2. Than wait or do something until your battery is down to 20%, shut the display off for the same time, kill recent apps and start Antutu test run again and compare the results.
I've also tried the same after a reboot, with always the same results.
With 100% I get scores between 60 and 66k and with lower capacity (20%) I get only 48 till 50k!
I am not interested about the benchmark results, but I need to know if this only occurs on my side.
Click to expand...
Click to collapse

So, guys!
I have tested it the last few weeks and it is a fact that the performance in benchmarks is dependent by the battery level.
We have tested it with 3 devices and it is always the same.
But thank God, it seems on the devices perfomance themselves (in apps/ui) this has no effect!
But each one can replicate this behavior very easy!

ollimi1 said:
Hi Jemcik, hi Denhot!
I'm facing the same issues on my new device and it's definately not normal!
With a battery level of 19% I was not able to get the 4 A57 cores online, which results in lower system performance. Have you found a solution?
@Denhot!
Maybe we should rename the thread into: IS OPT PERFORMANCE REALLY DEPENDENT ON BATTERY STATUS AND IS IT A ROM FEATURE OR AN ISSUE!?
I think, one of the kernel devs should be able to answer this question.
Click to expand...
Click to collapse
I have the same issue! When battery level goes lower than 20%, my A57 kernels become offline. I checked this with CPU-Z and PerfMon. And this is the same on stock or custom kernel. Now I am using Boeffla kernel. The most frustrating is that my UI suffer from this. I have lot of lags in simple apps, such as calculator or some messengers.

Same issue here, there are threads in one plus forums.
I think the threashold level is at 40 % ?? They made this to keep the battery up. You can also see faster battery drop till the 40-30% mark then it is harder to kill the battery.
I am also dissapointed in this, maybe we can search the kernel sources ? Or is there a daemon app that triggers this?
I received the phone with 20%-30% battery, started an antutu knowing how powerfull 810 chip is, then boom 45k same as the previos phone i had with 801 chipset...i was like what the fxck....runing antutu again with full battery - 66k.

well i have run benchmark in back ground with few game and apps .. and checked with cpuz max that i have notice was around 50-60% cpu load still 2 off those a57 cores were off using this device for 2-3 days it always turns off 2 cores for me rest 6 is working most of the time :/ Even in battery saver mode .. i am not sure if this is a cpuz issue as i have not rooted my device yet so cant say properly ..
Also i face some freq. benchmark issue like in benchmark it scores around single core - 690 multicore - 2.6K .. and if i restarts device it scores normal - 1.1K and 4.5K .. i have no idea whats wrong with this :/

20% Battery Mark
The drop in performance at 20% Battery is standard behavior of the Rom and Stock Kernel. The Big Cluster (A57) is completly shut down to save Battery. If you dont want this you have to use a custom Kernel which is able to switch this Battery saving strategy off. Boeffla Kernel for example can do that.

Read http://www.anandtech.com/show/9828/the-oneplus-2-review/2.
They "optimized" the soc.....
No they just turned off some cores so there is no heat problem.
So I think this is my first and latest oneplus.

they've hit the mark! What the hell, i think they must be sued for false marketing. Its just like buying a car with 400 hp and those hp are only there when i'm parked or listen to music, if i'm on the highway or on the ridge the car has 100 hp...wtf :|

Killer2k8 said:
they've hit the mark! What the hell, i think they must be sued for false marketing. Its just like buying a car with 400 hp and those hp are only there when i'm parked or listen to music, if i'm on the highway or on the ridge the car has 100 hp...wtf :|
Click to expand...
Click to collapse
Calm down lol it's actually good on their part. Shutting down A57 cores on low battery is a good thing because the A53 cores use much lesser battery. If you're out on a trip and have 10% battery, with the A57 cores this will probably drain off within an hour of intermittent usage. When only the A53 cores are active, the battery life will increase greatly.
Companies design phones for average users, not just gamers. If you don't want this feature, root your phone, flash boeffla's kernel and disable the BCL Battery Driver. It's as simple as that

Which rom has a good battery life?

Hey i tried many diffrent rom bui i can only get 2.5h SOT. Which kernel do you use and which rom to get the maximum battery life without lag?

Battery<----------------------------------->Performance
They are at opposite ends. If you want maximum battery life then there no way to avoid lag.
You can completely turn off 2 or 3 cores, leaving you with a single or dual core phone;
You can also underclock and undervolt the remaining cores, reducing power consumption even more.
This is very battery friendly (in theory), but, as I said, it will give you big lags.
I added a rom video review to the help thread. You might want to check it out.

obol2 said:
Hey i tried many diffrent rom bui i can only get 2.5h SOT. Which kernel do you use and which rom to get the maximum battery life without lag?
Click to expand...
Click to collapse
Sounds like you really need a new battery
GDReaper said:
Battery<----------------------------------->Performance
They are at opposite ends. If you want maximum battery life then there no way to avoid lag.
You can completely turn off 2 or 3 cores, leaving you with a single or dual core phone;
You can also underclock and undervolt the remaining cores, reducing power consumption even more.
This is very battery friendly (in theory), but, as I said, it will give you big lags.
I added a rom video review to the help thread. You might want to check it out.
Click to expand...
Click to collapse
Don't mean to troll, but can't help it. Turn a quad core cpu into a dual core? Really?!
Erm... ok.

thundastruck said:
Don't mean to troll, but can't help it. Turn a quad core cpu into a dual core? Really?!
Erm... ok.
Click to expand...
Click to collapse
Do you have any better ideas on how to increase battery life?
Cores need power to run. Turning them off is a completely logical option.
You really don't need all the cores for most tasks. You can browse Facebook, or whatever, just fine with only two cores.
I am currently running in dual-core mode with max cpu frequency at 1.2 GHz and it still is smooth.

GDReaper said:
Do you have any better ideas on how to increase battery life?
Cores need power to run. Turning them off is a completely logical option.
You really don't need all the cores for most tasks. You can browse Facebook, or whatever, just fine with only two cores.
I am currently running in dual-core mode with max cpu frequency at 1.2 GHz and it still is smooth.
Click to expand...
Click to collapse
I aldeady underclockt it to 1.2 ghz and undervolting it -625000 uV. Shut off to cores and use intellimm. I also under clock gpu to 320 mhz and under volt it 1 step down. I use zen with 1024 kb. Turn off android logger and zram. Use amplify, power nap, greenify and Max 700 mhz screen off. What I can do more?

obol2 said:
I aldeady underclockt it to 1.2 ghz and undervolting it -625000 uV. Shut off to cores and use intellimm. I also under clock gpu to 320 mhz and under volt it 1 step down. I use zen with 1024 kb. Turn off android logger and zram. Use amplify, power nap, greenify and Max 700 mhz screen off. What I can do more?
Click to expand...
Click to collapse
Nothing.
Test your battery. Or better yet, start thinking of getting a replacement or a new phone. With a 2 hour charge something seriously is wrong with your device.
My 3 year old S4-i9500 still comfortably gets through the day. Bought a brand new original battery 6 months ago. Smooth sailing. No under-volting, shutting off cores, under-clocking or any crap like that. Phone is custom rom'med and correctly so if I may add.

obol2 said:
I aldeady underclockt it to 1.2 ghz and undervolting it -625000 uV. Shut off to cores and use intellimm. I also under clock gpu to 320 mhz and under volt it 1 step down. I use zen with 1024 kb. Turn off android logger and zram. Use amplify, power nap, greenify and Max 700 mhz screen off. What I can do more?
Click to expand...
Click to collapse
lower values for read ahead cache are more battery friendly.
Also, bfq is considered more battery friendly too.

thundastruck said:
Nothing.
Test your battery. Or better yet, start thinking of getting a replacement or a new phone. With a 2 hour charge something seriously is wrong with your device.
My 3 year old S4-i9500 still comfortably gets through the day. Bought a brand new original battery 6 months ago. Smooth sailing. No under-volting, shutting off cores, under-clocking or any crap like that. Phone is custom rom'med and correctly so if I may add.
Click to expand...
Click to collapse
In two month I will get a new phone. I want to buy the lg v10 but don't know if it is worth or lg g4 / moto x style.

obol2 said:
In two month I will get a new phone. I want to buy the lg v10 but don't know if it is worth or lg g4 / moto x style.
Click to expand...
Click to collapse
Never heard of these models except for lg g4, which was crap imo.

thundastruck said:
With a 2 hour charge something seriously is wrong with your device.
My 3 year old S4-i9500 still comfortably gets through the day
Click to expand...
Click to collapse
You are aware that he said 2.5h SOT, "screen on time" ?
That means that after using it for an entire day or two, the combined time of the screen being on is 2.5 hours, and in my opinion that is not really bad.
The screen is always the culprit when it comes to power consumption, and in a phone with a battery that doesnt exeed 2000mah its just natural
that after about 2-3 hours of the screen being on the little battery is empty, and no ammount of undervolting will extend that significantly.
The only thing he can consider to increase SOT is a bigger battery, if he doesnt mind the bigger bulge at the back.

Backe888 said:
You are aware that he said 2.5h SOT, "screen on time" ?
That means that after using it for an entire day or two, the combined time of the screen being on is 2.5 hours, and in my opinion that is not really bad.
The screen is always the culprit when it comes to power consumption, and in a phone with a battery that doesnt exeed 2000mah its just natural
that after about 2-3 hours of the screen being on the little battery is empty, and no ammount of undervolting will extend that significantly.
The only thing he can consider to increase SOT is a bigger battery, if he doesnt mind the bigger bulge at the back.
Click to expand...
Click to collapse
Had no idea - never really cared what SOT stands for anyway! But thanks for clearing that up. Always had satisfactory battery life on my S4. The few times I didn't was when a rom on my phone went bad & subsequently had to flash another.
So if what you say is true regarding a day or 2 battery life, then what is this chump complaining about? Turning water into wine? :silly:

So @GDReaper idea is right!I currently am on crDroid and when I switch off 2 or 3 cores the phone is as fast as it was and the battery lasts a little bit longer..With normal charging it goes to full for about 1 hour and half and without using it the batttery lasts 1-2 days,using it lasts about 3 hours or 4.I flashed a new kernel and turned on fast charging on Kernel Adiutor,now the phone charges full for about 45 minutes and lasts same! I'm very happy with my battery bcs I haven't changed it since I got the phone!

4 cores stopped

Hi all,
I have cpu z installed and I'm not rooted. It generally uses all 8 cores but when I accidentally opened it I saw that it was only using 4 cores. I decided to restart and it is still using 4 cores. Is this normal because my g5 plus always uses all 8 cores.

Your in low power or battery saver mode... look at the battery symbol.. I can't remember if it kicks in at 5% or 15% battery automatically, then turns off when you connect the charger... It sometimes takes a few minutes for everything to kick back in. I would bet after getting a decent charge it was back to normal?
There is also a issue with Nougat at newer reporting CPU usage incorrectly even in rooted devices... been talked about a lot, something in the stock Moto firmware (or maybe that was a different Moto, I get them confused sometimes).

Ok thanks. Apparently cpu z was wrong.

the cores are reduced to 4 when u are on battery saver.

On thanks. The weird part was I didn't turn the battery saver.

DarthMaul14 said:
On thanks. The weird part was I didn't turn the battery saver.
Click to expand...
Click to collapse
It's automatic at a certain battery level by default.

Oh ok. Does the same thing apply for quad cores and hexacores.

DarthMaul14 said:
Oh ok. Does the same thing apply for quad cores and hexacores.
Click to expand...
Click to collapse
It will throttle them, although the exact implementation varies somewhat depending on the actual processor. littleBIG architecture tends to be that the BIG cores get shutdown, on more standard architecture like the SD625 they will get throttled to 50-75% of maximum speed, and others may just get a couple random cores disabled, it depends on the CPU and how Qualcomm/MediaTek/whoever engineered it.

Ok thanks!