Hello,
I am not sure that undervolting can increase battery life. I even think it's the opposite effect
Demonstration :
Increasing battery battery life means using less power.
Power (P) is : P=U(voltage) x I (Intensity)
Most energy used by processors is converted in heating. It is like a resistance.
Voltage for a resistance is U = R x I. (ohm)
So Power used by the processor is P = U * I = R * I * I = R x I^2
So to reduce energy consumption, we have to reduce P. We cannot change R, so we should decrease Intensity.
Power used by processor cannot be change. So if we undervolt, intensity is increasing so the processors heats more and it is the opposite effect.
So why undervolt?
for me undervolting isnt giving any improvements in battery life. Furthermore, cpu and gpu isnt "eating" so much power as turned on screen ;D just my 50cent
And this thread is in the development forum because............?
Sent from my Samsung Galaxy Note II using xda premium
ph03n!x said:
And this thread is in the development forum because............?
Sent from my Samsung Galaxy Note II using xda premium
Click to expand...
Click to collapse
Because I found no better place where to open it?
{
"lightbox_close": "Close",
"lightbox_next": "Next",
"lightbox_previous": "Previous",
"lightbox_error": "The requested content cannot be loaded. Please try again later.",
"lightbox_start_slideshow": "Start slideshow",
"lightbox_stop_slideshow": "Stop slideshow",
"lightbox_full_screen": "Full screen",
"lightbox_thumbnails": "Thumbnails",
"lightbox_download": "Download",
"lightbox_share": "Share",
"lightbox_zoom": "Zoom",
"lightbox_new_window": "New window",
"lightbox_toggle_sidebar": "Toggle sidebar"
}
Just a guesstimate here, but switching a transistor is equivalent to charging/discharging a capacitor. There is a known switching voltage for a given transistor and the idea is that within a clock cycle you can switch the transistor between states. If you lower the applied voltage (v1 to v2) it takes longer for the transistor to reach its switching voltage (vs) which is why you sometimes need to overvolt to overclock. This uses less power as E=0.5CV^2 i.e. charging the transistor to a lower voltage requires less energy.
I'm not sure how correct this is but hopefully someone can let us know.
Generally undervolting mobile phones doesn't have much effect as the antennas, and screen have a much larger effect than shaving one or two percent from the poqer consumption of an already efficient chip.
Sent from my GT-N7100
tomh235 said:
Just a guesstimate here, but switching a transistor is equivalent to charging/discharging a capacitor. There is a known switching voltage for a given transistor and the idea is that within a clock cycle you can switch the transistor between states. If you lower the applied voltage (v1 to v2) it takes longer for the transistor to reach its switching voltage (vs) which is why you sometimes need to overvolt to overclock. This uses less power as E=0.5CV^2 i.e. charging the transistor to a lower voltage requires less energy.
Sent from my GT-N7100
Click to expand...
Click to collapse
Okay thank you for your answer, but a capacitor doesn't consume energy, it is always its internal resistance. So my argument is still valid..
Undervolting and lower performance goes hand in hand. If you undervolt the cpu, than it takes more time to do it's job, so you don't save juice, and if you need to wait while the screen is on, than you even loose.
liljom said:
Undervolting and lower performance goes hand in hand. If you undervolt the cpu, than it takes more time to do it's job, so you don't save juice, and if you need to wait while the screen is on, than you even loose.
Click to expand...
Click to collapse
Under volting does not decrease performance. Please read up in what it is. I can't even be bothered to correct you...
Sent from my GT-N7100 using xda premium
And what about the reduced voltage reducing the power, resulting is less energy lost to heat? Your cpu is processing at a given clock speed, that determines the speed of the system - less heat means the cpu can run faster for longer without overheating.
Actually, I don't see how that doesn't equate to lower consumption... your equation assumes a substitution for v but doesn't consider the scaling of r with t.
Sent from my GT-N7100 using Tapatalk 2
I agree with Edga, the time and effort you will spend finding the correct voltage values will not worth it. Even if you find some then the increase will be around 5-6%, (that's my experience from GS2, wasted some weeks to find stable values!!) for which I am not wasting my time. Else depends on you.
And the question belongs to Q&A section. This section is for Developers and related.
I'm understanding the logic but what about when the processor has no work to do. Example when Screen is off
Sent from my SGH-T889 using xda app-developers app
Basicly for direct current electronical devices (such as chips) P=V x I. There are 2 variables and we can only control one; Voltage.
Luckily the Voltage = R x I.
Thus I = V/R
and we can say P = V x (V/R)= V x V X R So simply the power equation is dependent to R and V.
This is how things are; we send a voltage to chip which has a constant R and it defines the current (I) with its pysical constructions (we can not change it, it is its nature) accourding to the equaiton of V=R x I. According to the power equation, since it has 2 Vs the increase in the power consumption is related to V^2, not V. So if you increase the voltage %10 this will result 110x110/10000= 1.21= %21 more power to be demanded from the battery.
Since they are nanometer sized dices they have a minimum current point to work. Current can be told as the amount of electrons to go + pole from - pole. Enough amount of electrons trigger the message in the transistor to work, rest produces heat and slowly kills the chip. However they are so small and a few molecules make difference and the manufacturer has no time to test each unit to determine the correct currents and adjust the voltage according to it. Besides it would also require unique software for each unit too. So they estimate the worst case scenerio and try to guess the chip with most faulty production and adjust the voltages including it.
This worst chip is mostly imaginary, a possibility but still they can not affort to take any risk for a few lower degrees heat and maybe 1/2 hour more battery time. Besides Android makers simply do not even care about it unlike the Microsoft or Apple pruducts. They have to make better estimations because their chips can not be under/overvolted nor OCed. This is probably why Nexus 4 has thermal issues. Google wanted to allow developers to OC easily by trusting the 28Nm build but it turned out to be a bad idea with these voltage values.
Highschool level physics should tell you undervolting increases battery life...by how much...who knows.
The goal is to reduce the amount of watts the device consumes.
Power (W) = Voltage (v) * Current (amps)
Now the problem with this formula is we cannot use this to estimate on non constant variables, as we can adjust voltage, but one also must think amperage is also changed, so we need to get a formula that includes resistance which should be constant.
P = IV, V = IR, I = V/R so using some basic arithmetic we can get the formula (I'm not going to show the work)
P = V^2/R
As you can see reducing the voltage, has an exponential effect in reducing power usage...
So say we go from using 1.3125v (which is my stock at 1.6ghz) to 1.2v.
At 1.2v it will use only 83.6% of the energy compared to what it needs at 1.3125v to do the same job. This equates to an energy savings of 16.4% again this is only for the processor.
Undervolt the GPU, then the memory and internal voltage...it can all add up.
Edit...I see _delice_doluca_ has already posted a good explanation...I should of read the whole thread first
The truth - my and many others experience : more than 1/2 hour sreen on and lower temperature. Silicon/transitors/chip love low temperature. At lower temp, transitor can work at higher speed. Don't you want more speed and still have good battery life + temp?
For me, the time finding stable volt = reasonable. I spend max = 1- 2 days to find with difference kernel!
Sent from my GT-N7100
the only different for me is temperature, for battery saving, always not noticeable for me, placebo effect most likely
Daemos said:
Highschool level physics should tell you undervolting increases battery life...by how much...who knows.
The goal is to reduce the amount of watts the device consumes.
Power (W) = Voltage (v) * Current (amps)
Now the problem with this formula is we cannot use this to estimate on non constant variables, as we can adjust voltage, but one also must think amperage is also changed, so we need to get a formula that includes resistance which should be constant.
P = IV, V = IR, I = V/R so using some basic arithmetic we can get the formula (I'm not going to show the work)
P = V^2/R
As you can see reducing the voltage, has an exponential effect in reducing power usage...
So say we go from using 1.3125v (which is my stock at 1.6ghz) to 1.2v.
At 1.2v it will use only 83.6% of the energy compared to what it needs at 1.3125v to do the same job. This equates to an energy savings of 16.4% again this is only for the processor.
Undervolt the GPU, then the memory and internal voltage...it can all add up.
Edit...I see _delice_doluca_ has already posted a good explanation...I should of read the whole thread first
Click to expand...
Click to collapse
I agree with you, but my demonstration on first post is also true ! So why is it opposite...?
Was this moved into dev discussion from elsewhere? (If so, can the person who moved it please PM me?)
Regardless, the OP seems to be making things more complicated than they need to be - and is also making an incorrect statement.
The overall power used by the processor CAN be changed.
The effect is similar to running a gasoline (petrol) engine with an overly rich fuel/air mix (which is usually done by most car manufacturers to compensate for poor fuels.)
Once you take into account that the power isn't fixed for a given speed, you can see that voltage can be reduced without raising the current - and has the effect of LOWERING (not raising) the heat resistance. (R=V/I - so if V is lowered and I remains the same, R must drop.)
That being said, the real-life impact of under-volting is usually negligible when compared to the overall drain of other aspects of the device (such as the radios and screen.)
Power = voltage^2 / resistance
So lowering the V of cpu there is a squared decrease
Resistance is constant mostly
Sent from my GT-N7100 using Tapatalk 2
Raphy511 said:
Hello,
I am not sure that undervolting can increase battery life. I even think it's the opposite effect
Demonstration :
Increasing battery battery life means using less power.
Power (P) is : P=U(voltage) x I (Intensity)
Most energy used by processors is converted in heating. It is like a resistance.
Voltage for a resistance is U = R x I. (ohm)
So Power used by the processor is P = U * I = R * I * I = R x I^2
So to reduce energy consumption, we have to reduce P. We cannot change R, so we should decrease Intensity.
Power used by processor cannot be change. So if we undervolt, intensity is increasing so the processors heats more and it is the opposite effect.
So why undervolt?
Click to expand...
Click to collapse
You are all in the wrong category of electronics, I or current does not exist as a constant in transistors. Semiconductor physics are different from normal macro-electronics. The same principles still apply but they are meaningless as their magnitude are lowered to nothingness.
Main power dissipation and power consumption is caused by dynamic leakage on the transistor gate while it is switching. Secondary power consumer is static leakage caused between gate and the body.
The usual simplified formula for CMOS transistors is expressed as
Power = Voltage² x Frequency x Capacitance
or
P = V² x f x C
That's basically it in very simplified terms. And as ewdinpang said, lowering voltage has a squared power decrease in the dynamic leakage power. This has been measured and proven, from myself included.
The full expanded forumula is here:
emprize said:
the only different for me is temperature, for battery saving, always not noticeable for me, placebo effect most likely
Click to expand...
Click to collapse
This is a nonsensical argument, temperature aka heat, is power. If you are getting a less heated phone, then your battery life is improving. If this wouldn't be the case then you are holding the solution to the world's energy problems in your hands.
AndreiLux said:
You are all in the wrong category of electronics, I or current does not exist as a constant in transistors. Semiconductor physics are different from normal macro-electronics. The same principles still apply but they are meaningless as their magnitude are lowered to nothingness.
Main power dissipation and power consumption is caused by dynamic leakage on the transistor gate while it is switching. Secondary power consumer is static leakage caused between gate and the body.
The usual simplified formula for CMOS transistors is expressed as
Power = Voltage² x Frequency x Capacitance
or
P = V² x f x C
That's basically it in very simplified terms. And as ewdinpang said, lowering voltage has a squared power decrease in the dynamic leakage power. This has been measured and proven, from myself included.
The full expanded forumula is here:
This is a nonsensical argument, temperature aka heat, is power. If you are getting a less heated phone, then your battery life is improving. If this wouldn't be the case then you are holding the solution to the world's energy problems in your hands.
Click to expand...
Click to collapse
*Nerdgasm*
I think....I Love you
Related
I just downloaded setcpu and as I was setting the profiles, I wondered if the frequent changing of CPU speeds could damage anything. For example, when the screen turns off, I set the speed to a low value, because I won't be using anything at that point. But when I start using the phone, it scales up to a bit higher speed. When the phone is charging, its at max speed, 995mhz. When the battery drops below 20%, the speed drops really low to conserve battery. Will these different scale values damage anything?
under clocking the phone will not have near the possibility of damaging the processor as over clocking. The main thing to worry about is the thermal specification of the processor. If you ride that limit too long, or surpass it, then you risk greatly reducing the life of your phone. But under clocking as in your case does not normally present that same form of danger.
elegantai said:
under clocking the phone will not have near the possibility of damaging the processor as over clocking. The main thing to worry about is the thermal specification of the processor. If you ride that limit too long, or surpass it, then you risk greatly reducing the life of your phone. But under clocking as in your case does not normally present that same form of danger.
Click to expand...
Click to collapse
bravo bravo!! /clap
if only we could install a xigmatek dark knight cooler on this thing. we could oc to 3ghz lol
Question: if the kernel will go into deep sleep whenever it has nothing to do, what is the benefit in regards to power consumption of pinning the clock speed real low when the screen is off?
I ask because common knowledge, at least from what I've seen around, is that the low-clock "screen off" profile is common sense. But today I tried not having that profile, and I see that the CPU goes into deep sleep a lot more time now, and my battery life is the same if not actually better than before.
True, ROMs and kernels are still changing so much that it's difficult to dedicate enough time to one configuration to actually determine it's efficiency over time, which is why I wanted to throw this out here, see if anyone with more knowledge can answer.
If the CPU is under a certain amount of load, I would imagine that, for instance, in an Ondemand governor with a very low Up Threshold, the CPU will spike to a high speed until it's done, then sleep the rest of the time until the next load. If constrained to a low clock speed, it'll work on it, slow but steady, until it's done.
Is the high voltage required for that spike offset by the voltage savings of going to sleep, and is the total voltage consumption at the end of the load lower than the alternative, that is, stick to a low clock cycle, consuming what I assume is lower voltage, but for a longer amount of time? Is voltage consumption as clock cycle speed increases linear, or exponential?
If the power consumption increases exponentially as clock speed increases linearly, then it might be better for power consumption to restrict the processor to lower speeds. But if power increase is linear, then it would be better, I believe, to let the CPU finish with it's load as fast as it can, so it can go to sleep faster.
Any thoughts, ideas?
To Quote from Wikipedia's Overclocking page:
Increasing the operation frequency of a component will usually increase its thermal output in a linear fashion, while an increase in voltage usually causes heat to
increase quadratically
Click to expand...
Click to collapse
I know nothing about the Galaxy S II specifically, but most Android phones scale both voltage and clock-speed together, leading to exponential power increases when clocking up. Thus, in theory, you should see better battery life with a lower CPU limit with screen-off.
If in your case you have constant voltages across the board, that would explain why you see no benefit from a screen-off profile.
Finally, if you do have constant voltages across clock-speeds, then you probably could lower your voltages at lower speeds and thus realize a benefit.
YMMV, of course
Yes but if you have processes running in the background like large file downloading then the phone won't be able to process any of them
Sent from my SGH-T989 using xda premium
Quick questions:
1) Is power usage by the CPU DIRECTLY affected by voltage? For example, does 1V use twice the power of 0.5V? ...or is it not a linear response like that?
2) Does the frequency (at same voltage) influence power usage by the CPU? Ex. 1.0GHz vs 1.1GHz, both at 1V.
Sent from my LG-P930 using Tapatalk 2
yes no
Flyview said:
1) Is power usage by the CPU DIRECTLY affected by voltage? For example, does 1V use twice the power of 0.5V? ...or is it not a linear response like that?
Click to expand...
Click to collapse
Yes, it's linear. The formula is P=I*V where P is power, I is current, and V is voltage.
2) Does the frequency (at same voltage) influence power usage by the CPU? Ex. 1.0GHz vs 1.1GHz, both at 1V.
Click to expand...
Click to collapse
Yes, definitely, because when running at a higher frequency, the CPU will be drawing more current (see above formula). That's the whole reason that CPUs will slow themselves down when not needed.
drumist said:
That's the whole reason that CPUs will slow themselves down when not needed.
Click to expand...
Click to collapse
When idle, CPU's slow down not only frequency but voltage too. Thats why cpu's consume less energy on lower frequencies. Processor on the same volgate, but different frequencies consumes almost the same power.
-ReaL- said:
When idle, CPU's slow down not only frequency but voltage too. Thats why cpu's consume less energy on lower frequencies. Processor on the same volgate, but different frequencies consumes almost the same power.
Click to expand...
Click to collapse
Dynamic power consumption is directly (linearly) affected by frequency, but static (leakage) power consumption is a different beast. I may be overestimating how big the dynamic power consumption is in comparison to static with these tiny SoCs.
drumist said:
Yes, it's linear. The formula is P=I*V where P is power, I is current, and V is voltage.
Yes, definitely, because when running at a higher frequency, the CPU will be drawing more current (see above formula). That's the whole reason that CPUs will slow themselves down when not needed.
Click to expand...
Click to collapse
Yes, that's what I'm wondering. Is the voltage and current increased with higher frequency or just voltage? If just voltage then the power use of any two frequencies at the same voltage is the same. If current also changes based on frequency, then two frequencies at the same voltage would use a different amount of power.
Sent from my LG-P930 using Tapatalk 2
Flyview said:
Yes, that's what I'm wondering. Is the voltage and current increased with higher frequency or just voltage? If just voltage then the power use of any two frequencies at the same voltage is the same. If current also changes based on frequency, then two frequencies at the same voltage would use a different amount of power.
Click to expand...
Click to collapse
No, current increases with frequency. But there is also a certain amount of power that is consumed no matter what the frequency is (so having a very low frequency doesn't mean it's consuming almost no power -- it just means it's consuming LESS power). I'm kind of oversimplifying it in my last post. It's complicated stuff, and I don't claim to be an expert at it. I'm just an amateur.
---------- Post added at 02:54 PM ---------- Previous post was at 02:13 PM ----------
I've been researching this a little bit since I have some free time and it caught my interest. Here's what I've come up with:
P ≈ k₁·V²·f + k₂·V
k₁ and k₂ are constants. (They have meaning but it's not necessary that we understand them.) V is voltage, and f is frequency. The first term (k₁·V²·f) is dynamic power, and the second term (k₂·V) is static or leakage power.
Some things to take away from this is that power consumption is more than halved when the voltage is halved. Even though it would appear that reducing the frequency only influences the dynamic power, the CPU automatically scales the voltage down when the frequency is lower, so as a chain reaction, the static power is also reduced significantly. (And as it happens, the static power is larger than dynamic power with modern chips, so that's important.)
Again, I'm not an expert on this. If someone sees an error or misunderstanding let me know.
Where is current in your formula? I know the CPU has voltages you can set for each frequency, what you would call the static voltage, but what is this dynamic power? Let's say I run the phone at 1.51Ghz at 1087.5mV. Would it consume more power than running at 1.35Ghz, if also set at 1087.5mV?
Sent from my LG-P930 using Tapatalk 2
Flyview said:
Where is current in your formula? I know the CPU has voltages you can set for each frequency, what you would call the static voltage, but what is this dynamic power? Let's say I run the phone at 1.51Ghz at 1087.5mV. Would it consume more power than running at 1.35Ghz, if also set at 1087.5mV?
Click to expand...
Click to collapse
The current is incorporated in the frequency term. The reason the dynamic power term has frequency in it is because the current drawn is proportional to the frequency. Basically, current equals frequency times a constant, which was absorbed into k₁.
Yes to your last question, but it may not be a huge difference.
Hey all, this is a thread I saw on different forum and think it is would be good for noobs like myself to benefit from. How to undervolt your CPU and also post your Galaxy Note 2 specific results. I have tried these next steps, and so far I'm doing okay (can't give an accurate results on battery life yet). Like I said (I'm not ashamed to say I'm a noob) but if others can throw their two cents in, we can all learn and this thread can be useful. The next part was cut and paste d from other forum. And I deleted the url for the kernel and root
Prerequisites:
1. Must be rooted and recommended kernel
2. Download and install System Tuner
3. Download and install Stability Test
Steps:
1. Open System Tuner and select CPU
{
"lightbox_close": "Close",
"lightbox_next": "Next",
"lightbox_previous": "Previous",
"lightbox_error": "The requested content cannot be loaded. Please try again later.",
"lightbox_start_slideshow": "Start slideshow",
"lightbox_stop_slideshow": "Stop slideshow",
"lightbox_full_screen": "Full screen",
"lightbox_thumbnails": "Thumbnails",
"lightbox_download": "Download",
"lightbox_share": "Share",
"lightbox_zoom": "Zoom",
"lightbox_new_window": "New window",
"lightbox_toggle_sidebar": "Toggle sidebar"
}
2. Drag the slider shown in the picture to overclock or underclock CPU. In this picture we are overclocking to 1.8ghz
3. Select Voltage at the top to get to CPU voltage settings.
4. Ok, here select the buttons as they are in the picture.
a. Select the Green circled button to save current stock default settings.
b. Select the Yellow circled button 4 times exactly to reduce the millivolts by 100.
Stability Testing:
Now we really should make sure that it can handle it under load right? :silly:
1. Open Stability Test and select CPU+GPU Stability Test.
2. Select Full Details - Proceed.
3. The app will now start stressing your cores. I waited until at least 10 cpu passes before quiting the app...
Cliffnotes:
-By default, your settings will revert back after you restart your phone. You can set them to load at boot, but don't do this unless your absolutely sure that they're stable!
Open System Tuner - CPU - Menu key - Settings - Active Tweaks - Reapply CPU Settings - On Boot Completed
-Whenever i tried to lower the mv more than 100 below stock at 1.8ghz, my phone rebooted
-I am in no way responsible for anything that might happen after performing the above, even if you start your sentence with the word "but"
-here's stock settings in case you need to revert
[/QUOTE]
This is an interesting project but I would think that the average user would not need this as battery life is pretty good. Speaking for myself, I am able to get through the whole day without any issues.
Of course there might be other reasons why someone would want to do this.
Doc
Thanks
Sent from my SGH-I777 using xda premium
DocEsq said:
This is an interesting project but I would think that the average user would not need this as battery life is pretty good. Speaking for myself, I am able to get through the whole day without any issues.
Of course there might be other reasons why someone would want to do this.
Doc
Click to expand...
Click to collapse
from what i've read, undervolting save very little battery time as the processors are pretty efficient anyways. i don't have actual numbers, but i'd guess you'd get a few extra minutes - which some may really need.
it's that freaking gargantuan screen that sucks the most juice. there used to be a mod to undervolt displays. they had it working on an OG galaxy tab. i never really seen it used anywhere else.
I have an international version of galaxy note 2. I'm currently using AllianceROM and Perseus kernel. And my stock voltage is way way higher than yours. Like 1400mV mine, 913mV yours. Can I undervolt my note 2 to same specifications like yours? Thanks.
This is interesting but setcpu when I had it on my last phone worked awesome and was very easy to use.
Sent from my Amazing Galaxy Note 2!
rjisanandres said:
I have an international version of galaxy note 2. I'm currently using AllianceROM and Perseus kernel. And my stock voltage is way way higher than yours. Like 1400mV mine, 913mV yours. Can I undervolt my note 2 to same specifications like yours? Thanks.
Click to expand...
Click to collapse
You is 1400 mV on 200 MHz? It's probabky 1400 on 1.6 ghz.
Sent from my SCH-I535 using xda premium
I also have Perseus kernel overclocked but still have great battery life. Thanks for the tip though might try it and compare the difference just in case.
I agree with DocEsq.. It is interesting indeed, but is it really necessary?
Can you overclock it?
My note 2 seems to be charging forever after undervolting. I'm talking for about 6-7hrs charging time here. What seems to be the problem? I'm using Perseus kernel. TIA!
Sent from my GT-N7100 using Tapatalk 2
I once conducted a test with my evo3d. I basically ran an amp meter inline with the battery. Measuring the exact power consumption. I dont remember the exact specs, but undervolting and underclocking my phone compared to stock made a very minute difference in actual power consumption. A difference of about 8-15ma. This was during a CPU full load scenario for about 10 seconds. Even loading the CPU with the screen off to take as many variables out as possible it was very little difference. During normal operarion the power consumed was virtually identical.
So the 2 to 3% of the day (overall time) your phone is actually under HEAVY load, it won't make much difference. It did make a performance impact. So not much benefit, just reduced performance.
Now overclocking and/or overvolting did make a larger difference in consumption at high constant load.
Want to ACTUALLY make a large impact on your battery life? Make sure you don't have any apps preventing your phone from sleeping and run the absolute lowest screen brightness you can stand.
YMMV.
Sent from my Galaxy Note 2 using Tapatalk 2
The benefit I found from undervolting isn't better battery life, it's reduced heat which in heavy use provides better performance due to no cpu throttling. I'm running 1800mhz using less battery than 1600mhz and with same temps as stock. Very stable, been running this for a month now at least.
Action B said:
The benefit I found from undervolting isn't better battery life, it's reduced heat which in heavy use provides better performance due to no cpu throttling. I'm running 1800mhz using less battery than 1600mhz and with same temps as stock. Very stable, been running this for a month now at least.
Click to expand...
Click to collapse
What app did you use to undervolt?
Sent from my Amazing Galaxy Note 2!
yankees45us said:
What app did you use to undervolt?
Sent from my Amazing Galaxy Note 2!
Click to expand...
Click to collapse
I'm using the stweaks app that comes with perseus kernel.. I've undervolted quite a bit and I get better battery life.. Still not quite as good as I had stock, but definitely a lot better for being over clocked.. I just reduce each level to the level below it and run for a few to check stability and keep going from there.. So far I have had no trouble at all with undervolting.. Certainly nothing like I did with my elte.. Here's where I've been for almost a week as well as today's battery results so far with Pandora playing over 3 hours straight and moderate use..
Sent from my SPH-L900 using Tapatalk 2
Yeah, just to let you know that there certainly isn't a linear correlation between undervolting and underclocking and power usage. That might have been the case in simpler times, but with modern multi-core microprocessors, you might actually be decreasing battery life by screwing with your clock rate or voltage. Yes, the defaults err on the side of caution, but it's a whole lot of work for little to no gain.
For example, by reducing your phone's clock rate, you might actually be forcing your phone to be spending more time at load; thereby not allowing it to fallback to its sleep state. There is also something called the power wall, where an increase in operating frequency requires an exponential increase in power. However, the reverse is also true. It can be counter-intuitive to think of it this way, so a practical example is how on a 100 mile trip, a 25 mpg sedan saves 4 gallons of gasoline over a 12.5 mpg SUV. However, over the same distance a 50 mpg hybrid saves only 2 gallons over the 25 mpg car. By that same logic, a mythical 100 mpg vehicle would only save 1 gallon of fuel. It's the law of diminishing returns. Then of course, there are the stability issues that you should take into account.
There is a lot that happens behind the scenes regarding power management. Your phone is capable of intelligently scaling it's processors, voltages, and frequencies up or down all based on current and expected demand. There are people who spend a lot more time doing this for a living, and the idea that you can do it better is probably a falsehood. If you want MOAR POWER, by all means overclock/overvolt it (just don't fry it), but trying to get an extra couple minutes of run time is likely a waste of some hard work. It's the software that kills your battery, not the hardware.
Talking about computer architecture can be complicated and boring, but start with searches on "rise time" and "logic level transitions" if you want to want more background.
Action B said:
The benefit I found from undervolting isn't better battery life, it's reduced heat which in heavy use provides better performance due to no cpu throttling. I'm running 1800mhz using less battery than 1600mhz and with same temps as stock. Very stable, been running this for a month now at least.
Click to expand...
Click to collapse
Interesting... whenever I'm dling using a torrent client my phone gets a nasty fever and I've gotta set it down somewhere as it will literally make me sweat, lol. I do b there think I'll be undervolting just for that specific circumstance but that is a very interesting concept...
anishannayya said:
Yeah, just to let you know that there certainly isn't a linear correlation between undervolting and underclocking and power usage. That might have been the case in simpler times, but with modern multi-core microprocessors, you might actually be decreasing battery life by screwing with your clock rate or voltage. Yes, the defaults err on the side of caution, but it's a whole lot of work for little to no gain.
For example, by reducing your phone's clock rate, you might actually be forcing your phone to be spending more time at load; thereby not allowing it to fallback to its sleep state. There is also something called the power wall, where an increase in operating frequency requires an exponential increase in power. However, the reverse is also true. It can be counter-intuitive to think of it this way, so a practical example is how on a 100 mile trip, a 25 mpg sedan saves 4 gallons of gasoline over a 12.5 mpg SUV. However, over the same distance a 50 mpg hybrid saves only 2 gallons over the 25 mpg car. By that same logic, a mythical 100 mpg vehicle would only save 1 gallon of fuel. It's the law of diminishing returns. Then of course, there are the stability issues that you should take into account.
There is a lot that happens behind the scenes regarding power management. Your phone is capable of intelligently scaling it's processors, voltages, and frequencies up or down all based on current and expected demand. There are people who spend a lot more time doing this for a living, and the idea that you can do it better is probably a falsehood. If you want MOAR POWER, by all means overclock/overvolt it (just don't fry it), but trying to get an extra couple minutes of run time is likely a waste of some hard work. It's the software that kills your battery, not the hardware.
Talking about computer architecture can be complicated and boring, but start with searches on "rise time" and "logic level transitions" if you want to want more background.
Click to expand...
Click to collapse
Like the way you put that. Good analogies there it just seems like the other day that undervolting was the hip thing to do. Technology just moves at such a wonderful pace though. Just one little FYI though, since i do like you analogy i would like to point out that the law of diminishing returns actually refers to something else entirely. I know, I know, nitpicking, but it's just that everyone is always off the mark with that one and, well I guess I'm just an anal ahole (and an economics major, ,which I guess just overall makes me an a hole, ,lol)
If you have ever pulled apart a laptop and saw how much thermal paste the engineers at the factory "designed" for their to be on there, or seen the air/fuel ratio most cars roll off the lot with, or ever replaced an intake in a vehicle with a high performance unit I'm not sure you would feel the same way about you yourself not being to do a better job.
I get the point, and I believe often there is validity to that point, but sometime things just aren't that simple. This is where power gains come from in tuning a car (which i do). This is where efficiency is raised by removing restrictive components in a vehicle (intake, exhaust, etc) and where cooling performance is increased on a CPU with the proper application of a quality thermal paste.
Whenever time is money, and you are deciding between your bottom line and something that works and something that works as well as it can, shortcuts are made and corners are cut. Perhaps they could have spent another 200 hours for the team to absolutely optimize the processor for each device, but the cost would have been an additional $20,000 dollars. This is not always the case, but with processors I think it is. I will undervolt everytime and I do take objective measures for battery and I agree gains are relatively small. For cooling, I found the difference to be very significant at 1800, mhzI didn't check at 1600mhz, however. I can run a full Antutu benchmark as much as I want at room temperature and never exceed the throttling point (70 C if i remember correctly). Now, I am in no way saying these are facts, these are opinions, so I could be wrong of course.
Psychotic-Cerebellum said:
Interesting... whenever I'm dling using a torrent client my phone gets a nasty fever and I've gotta set it down somewhere as it will literally make me sweat, lol. I do b there think I'll be undervolting just for that specific circumstance but that is a very interesting concept...
Like the way you put that. Good analogies there it just seems like the other day that undervolting was the hip thing to do. Technology just moves at such a wonderful pace though. Just one little FYI though, since i do like you analogy i would like to point out that the law of diminishing returns actually refers to something else entirely. I know, I know, nitpicking, but it's just that everyone is always off the mark with that one and, well I guess I'm just an anal ahole (and an economics major, ,which I guess just overall makes me an a hole, ,lol)
Click to expand...
Click to collapse
The TIM wasn't put on there by the engineers who designed the chips; they are put there by workers being paid next to nothing.
Your phone doesn't have a CPU, it doesn't even use thermal paste; it's usually just a rubber contact patch and passive heat dissipation. This actually brings another point where overclocking can sometimes reduce performance due to throttling by thermal constraints (why our phone has such a low GPU rate than what it is capable of in other phones with better thermal envelopes).
You aren't replacing the SoC, you are changing the software that determines how to set the voltage/clock multiplier. The car analogy isn't valid.
And I stand corrected regarding the Law of Diminishing Returns; never paid attention in macro-econ. I think was because my prof. was more interested in forcing his political ideology upon us than actually teaching the subject. :silly:
EDIT: Keep in mind, the engineers rarely get what they want. The product the consumer ends up getting is usually dictated through a collaboration of what the business and marketing teams want. The engineer might request a large cooler clamp with a perfectly lapped surface and a carbon-based TIM. In reality, the consumer gets a dinky fan with melt-on TIM and retention springs. Money talks.
anishannayya said:
The TIM wasn't put on there by the engineers who designed the chips; they are put there by workers being paid next to nothing.
Your phone doesn't have a CPU, it doesn't even use thermal paste; it's usually just a rubber contact patch and passive heat dissipation. This actually brings another point where overclocking can sometimes reduce performance due to throttling by thermal constraints (why our phone has such a low GPU rate than what it is capable of in other phones with better thermal envelopes).
You aren't replacing the SoC, you are changing the software that determines how to set the voltage/clock multiplier. The car analogy isn't valid.
And I stand corrected regarding the Law of Diminishing Returns; never paid attention in macro-econ. I think was because my prof. was more interested in forcing his political ideology upon us than actually teaching the subject. :silly:
EDIT: Keep in mind, the engineers rarely get what they want. The product the consumer ends up getting is usually dictated through a collaboration of what the business and marketing teams want. The engineer might request a large cooler clamp with a perfectly lapped surface and a carbon-based TIM. In reality, the consumer gets a dinky fan with melt-on TIM and retention springs. Money talks.
Click to expand...
Click to collapse
1. The voltages are set by an engineer, that is what I was referring to.
2. The CPU thing was an analogy as was the car. Not a direct comparison. The analogy is referring to how there is set fuel and timing tables just like there is set voltage tables, both might not be the most efficient from the factory, tweaking them can improve things. How is this completely not valid?
I have gained root privileges. As you know, pixel6Pro has a strict temperature limit. This means that once the temperature of the mobile phone rises to about 40°C, the processor will start to reduce the operating frequency. When it reaches 43°C, all cores will not be allowed to work at a frequency above 1G... This will cause the phone to freeze very much. So will there be any mods to turn it off? I have an extra phone cooler./translate form Google
So you'd rather it have unlimited temperature to cause components to melt? There's a good reason why there is a temperature limit. I suggest that you don't mess around with it, or you will end up with a heap of garbage.
96carboard said:
So you'd rather it have unlimited temperature to cause components to melt? There's a good reason why there is a temperature limit. I suggest that you don't mess around with it, or you will end up with a heap of garbage.
Click to expand...
Click to collapse
I mean to increase the upper limit instead of closing it ... I also have a Redmi K40, equipped with Snapdragon 870, and the phone temperature exceeds 48 ° C to start limiting the processor frequency ... In contrast, TensorG1's frequency limit from less than 40 ° C is too early..For example, at room temperature of 23 ° C, my Pixel6Pro played at a current of about 1A (power consumption of about 4W). About 15 minutes, the back cover temperature of the mobile phone would be close to 40 ° C, and then a disgusting frequency limit appeared. 40 ° C is very safe for the phone, isn't it? And the lower area of the Pixel6Pro heating speed is much faster than the camera area and processor area, which is not common sense, and I also want to know why.If the frequency limit starts at about 46 ° C, it will be a good choice.
I think people should study electronics first before they tinker. This is proof. MORE HEAT?
Gytole said:
I think people should study electronics first before they tinker. This is proof. MORE HEAT?
Click to expand...
Click to collapse
Thank you for your reply, but I can't understand what you mean by translating.
He means that different devices have different specification, and you will likely damage your device.
Arealhooman said:
He means that different devices have different specification, and you will likely damage your device.
Click to expand...
Click to collapse
But this is based on root, which has assumed that I bear all the consequences, right? Having said that, the Pixel6Pro is the phone with the lowest temperature limit I have ever used.Even the same garbage Snapdragon 888 chip has a frequency limit at about 43 ° C.I just use it to run small games, but it can't last for too long, which makes me wonder if this can be called a flagship phone. Leaving aside the peak performance, the Snapdragon 778G is much better than Tensor in many scenes.And Google made a lot of mistakes. In fact, the X1 core is much more efficient than the A76 core, but I don't understand why the more used is the A76 core? ? ? I like to test the power consumption data of the processor. After about half a month I conclude that [email protected] and [email protected] have almost the same performance, but the latter one needs to pay an additional power of about 0.25W+.Too crazy,right?
Juuuuune said:
But this is based on root, which has assumed that I bear all the consequences, right? Having said that, the Pixel6Pro is the phone with the lowest temperature limit I have ever used.Even the same garbage Snapdragon 888 chip has a frequency limit at about 43 ° C.I just use it to run small games, but it can't last for too long, which makes me wonder if this can be called a flagship phone. Leaving aside the peak performance, the Snapdragon 778G is much better than Tensor in many scenes.And Google made a lot of mistakes. In fact, the X1 core is much more efficient than the A76 core, but I don't understand why the more used is the A76 core? ? ? I like to test the power consumption data of the processor. After about half a month I conclude that [email protected] and [email protected] have almost the same performance, but the latter one needs to pay an additional power of about 0.25W+.Too crazy,right?
Click to expand...
Click to collapse
Its a different SoC and different phone altogether, and the temperature reading could be from a different point, and it takes time for the heat to be conducted from the point of highest temperature to the sensor, which means that when you have a READING of 40C, the actual highest temperature point could be 75C.
Arealhooman said:
He means that different devices have different specification, and you will likely damage your device.
Click to expand...
Click to collapse
But you won't. Removing the OEM throttling mechanism doesn't completely remove throttling. The SOC WILL throttle regardless of when it hits the set TjMax.
Also, the throttling they set is based on SKIN/Shell temperatures, usually on Pixel 6/7 starting around 37c SKIN, that's on the battery around 37c (all approximate). I don't own the Pixel 6, but the 7, and the SKIN temperature is set to start at 37c very mild throttling, and the more the temperature rises, the throttling level increases.
Ultimately, the "only" hardware that will suffer in the LONG RUN is the battery since batteries don't like high temperatures and degrade faster when exposed to XY temps.
Juuuuune said:
But this is based on root, which has assumed that I bear all the consequences, right? Having said that, the Pixel6Pro is the phone with the lowest temperature limit I have ever used.Even the same garbage Snapdragon 888 chip has a frequency limit at about 43 ° C.I just use it to run small games, but it can't last for too long, which makes me wonder if this can be called a flagship phone. Leaving aside the peak performance, the Snapdragon 778G is much better than Tensor in many scenes.And Google made a lot of mistakes. In fact, the X1 core is much more efficient than the A76 core, but I don't understand why the more used is the A76 core? ? ? I like to test the power consumption data of the processor. After about half a month I conclude that [email protected] and [email protected] have almost the same performance, but the latter one needs to pay an additional power of about 0.25W+.Too crazy,right?
Click to expand...
Click to collapse
The temperature limits DEPEND on the OEM. It's NOT SOC SPECIFIC.
CPU and GPU are MOSTLY set to 85c/95c on Qualcomm Snapdragon SOCs. Pixel 7 series has the CPU set to 100C TjMax (I think the GPU is set to 95c, didn't check...)
The throttling you're talking about is based on the SKIN/Shell and EACH OEM has its own way of tunning this throttling mechanism.
JohnTheFarm3r said:
The temperature limits DEPEND on the OEM. It's NOT SOC SPECIFIC.
CPU and GPU are MOSTLY set to 85c/95c on Qualcomm Snapdragon SOCs. Pixel 7 series has the CPU set to 100C TjMax (I think the GPU is set to 95c, didn't check...)
The throttling you're talking about is based on the SKIN/Shell and EACH OEM has its own way of tunning this throttling mechanism.
Click to expand...
Click to collapse
The temperature limit of a specific SoC is determined by the characteristics of *that SoC*, not by whoever glues parts together.
96carboard said:
The temperature limit of a specific SoC is determined by the characteristics of *that SoC*, not by whoever glues parts together.
Click to expand...
Click to collapse
I'm suggesting you go and check (inform/educate yourself) a bit on this topic and how exactly this works. A SOC has an operating temperature range (from-to), THAT IS VERY TRUE (and I'm not talking about the operating temperature range specification here) but OEM decides what TJMax they want to set on the CPU or GPU (or any other component inside the phone)
So, if the OEM wants, they can set the TJMax for the CPU at 110c or more. Obviously, they don't do this for various reasons and most importantly to decrease the degradation of the silicon as much as possible (lower temps, longer life). And if you're experienced enough and know how to configure the throttling you can raise the Tjmax yourself. Google raised the TjMax on Tensor G2 to 100c. G1 was set to 90c, but they could have set it to 100C too if they wanted. And this is done on the OS side. (OEM side)
For your information, on Tensor (both G1 and G2), you can raise the TJMax of the CPU or GPU (or any other component) just by editing the thermal zones inside sys/devices/virtual/thermal > Thermal Zones (needs root).
And as someone who already made various thermal mods (magisk modules for various devices), I'm VERY well aware of how is thermal throttling handled and what can be done.
JohnTheFarm3r said:
I'm suggesting you go and check (inform/educate yourself) a bit on this topic and how exactly this works. A SOC has an operating temperature range (from-to), THAT IS VERY TRUE (and I'm not talking about the operating temperature range specification here) but OEM decides what TJMax they want to set on the CPU or GPU (or any other component inside the phone)
So, if the OEM wants, they can set the TJMax for the CPU at 110c or more. Obviously, they don't do this for various reasons and most importantly to decrease the degradation of the silicon as much as possible (lower temps, longer life). And if you're experienced enough and know how to configure the throttling you can raise the Tjmax yourself. Google raised the TjMax on Tensor G2 to 100c. G1 was set to 90c, but they could have set it to 100C too if they wanted. And this is done on the OS side. (OEM side)
For your information, on Tensor (both G1 and G2), you can raise the TJMax of the CPU or GPU (or any other component) just by editing the thermal zones inside sys/devices/virtual/thermal > Thermal Zones (needs root).
And as someone who already made various thermal mods (magisk modules for various devices), I'm VERY well aware of how is thermal throttling handled and what can be done.
Click to expand...
Click to collapse
Thank you for your reply. In the file directory you mentioned, I found many files starting with "thermal_zone" followed by numbers. But I'm not good at this field, can you tell me more? I know you have a magisk module for pixel7Pro, I want to know if you can modify some parameters to make it work on pixel6Pro? （Or are they inherently universal?） I have a pixel6Pro which rooted , maybe it can be used for your test.