hi there.
I've been tinkering with voltages and cpu frequencies lately.
I noticed that, with stock voltage values, i have "900" for 122, 245 and 368 mhz.
Now the question is, leaving governors aside for a moment: if i set cpu minimum to 122 or 368, there shouldn't be any battery drain differencies, since they both have the same voltage value.
But technically if i have some background stuff going on, with screen off or when the phone is idle, they will be processed faster with 368 mhz, while with 122 they will take longer to carry on or even force the phone to work to get to a higher frequency to finish the task.
Now i maybe saying a lot of bullcrap since i'm not a developer nor a hardware guy,
but if what i said is true, then in theory it would not be the same if i put minimum to 368, it would actually be better for performance AND the battery??
No, as I have learned from another user here; even if the voltage is the same, the power draw is still different. 122mhz will still use the least amount of power
Hello,
Just wondering if anyone has experimented with Tegrak Overclock Ultimate's GPU optimization settings. It allows you to undervolt the GPU. Has anyone tried this and is there any benefit to battery life savings with this? I am playing around with the settings right now, so I'll post my results later. So far been able to undervolt the 267 mhz step by -75mv from 1000mv down to 925mv (900mv is unstable for me). And I undervolted the 160 mhz step by -150mv from 900mv down to 750mv. There is also a 200 mhz step I haven't played with. Perhaps keeping the GPU at 200/160 can yield potential battery savings when playing games because games drain the battery so fast.
Hm. I seem to be able to undervolt the 200 mhz step to 750mv as well. I'm going to run a 200/160 gpu setup at 750mv and see if I can save any battery playing Gun Bros and will let you guys know.
caaznkid said:
There is also a 200 mhz step I haven't played with. \
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Really? I only have the 267 and 160 MHz clock settings available. Any thoughts anyone?
Oh, I have underclocked my GPU settings but only by a modest 25mV each.
There's only 2 steps, but u can change the clock between 160, 200, and 267
yep ... good results
Yep I've been experimenting with GPU undervolting and had some sucess. So I was methodically working downwards and testing stability... then i saw this thread and thought what the hell, right? I shot for lowest mv of 750 and it's rock solid at 200mhz.
Can confirm 750mv stable at 100, 134, 160 and 200mhz. 267mhz can't be undervolted that much.
I've locked 200mhz 750mz for both speed steps and left it at that. Phone has yet to display any instability in a couple of days of mixed use including gaming. Battery life better? Subjectively yes, mostly I notice phone doesn't get so hot playing Dead Space.
Power consumption scales down almost linearly with clock cycles, and exponentially with voltage (right?). So by my math GPU is using about 40% of the power it does at full 267mhz. I wonder what the TDP of the exynos 4210 is and how much the Mali 400 contributes to that, would give some idea of what battery life to expect. Since GPU sits idle a lot, I doubt it's a magic fix.
Such is the power of our phones I have to underclock the CPU and GPU quite far before any 3D game gets too choppy to play. 160mhz is more than fine for most.
Usually undervolting makes the most sense for power saving because a given computing workload takes a certain number of cpu cycles. But 3D usually tries to render as many frames as it can, with the exception of S2's 60fps frame cap. So slowing down the GPU to no more than you need might improve gaming battery life?
My SGS2 is a bit sensitive to undervolting although underclocking of CPU, so I'm happy be able to so agressively undervolt the GPU.
I'd be interested to know who else can just set 200mhz & 750mv and have it rock solid? If not, 200/800 or 160/750?
I've rarely had problems when I use Tegrak. Then again, I undervolt 100mv on my cpu between 200-1000mhz, and about 50mv on my GPU at 267mhz with the noop scheduler and tweaks enabled. If I can get Tegrak to work with the Gunslinger kernel (currently causes reboot loops when I load the overclock module), I'll report back on battery life with Tegrak and experiment a little more.
jyaworski said:
I've rarely had problems when I use Tegrak. Then again, I undervolt 100mv on my cpu between 200-1000mhz, and about 50mv on my GPU at 267mhz with the noop scheduler and tweaks enabled. If I can get Tegrak to work with the Gunslinger kernel (currently causes reboot loops when I load the overclock module), I'll report back on battery life with Tegrak and experiment a little more.
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I had the same problem with Gunslinger, I decided to keep my phone on Rogue Stock EL29.
I've been able to drop my GPU Level 0 Clock to 160mhz and voltage to 850mv with out any issues.
I also keep my GPU 1 Clock at 100mhz and my voltage at 750mv without a problem.
Using noop of course.
Changing GPU clocks and volts doesn't help much.
Keeping your CPU Internal Voltage and Core Voltage -50mV and keeping it scaled 200-800 MHz will give you much better battery.
I think the effect would be more significant in ICS since ICS use GPU to render UI
Hello!
I recently noticed how frequencies 122MHz through 460MHz all employ the same voltage (900mV). I've come to understand that the higher the CPU frequency the faster your battery will drain. What I don't understand is why a higher frequency will drain your battery faster.
Is the only cause for higher battery drain when running a higher frequency, the higher voltage which comes with a higher frequency, or are there other factors?
If, then, a higher voltage is the only cause, then my battery would not drain faster if I clocked my minimum frequency at 460MHz instead of 122Mhz?
Thanks in advance to anyone who can shed some light on this!
Hi
cpu power consumption at a specific frequency is bound to its voltage.
you should test a voltage for a frequency while your device has 100% workload, because you could find a voltage so that your device is stable while being idle, but freezes when it needs to work. (for more information search for linux phc)
my conclusion:
the voltage for a specific frequency has minimum!
you can set your minimum frequency to 460 if you want to, since the screen consumes most power, it should not matter that much. i have set my minimum freq that high, too. I believe that way, my phone needn't raise the frequency when dooing simple stuff, like playing music.... but i am just guessing.
i theory it must get hotter than at lower frequencys, but i did not notice that.
i have had a palm pre and a custom kernel introduced a voltage on demand governor, which kept the device at 1ghz all the time, but changes the voltage with the workload. i think the developer of the awesome idea is "unixpsycho" ... i would like to see something similar on android.
greetings
matto
EDIT:
http://en.wikipedia.org/wiki/Dynamic_frequency_scaling
it looks like it is bound to the frequency, too!
~const*f*V^2
the Voltage is quadratic, that means it tkes a higher priorety.
e.g. lowering the voltage from 900mv to 800mv => (0.8^2)/(0.9^2) ~ 0.79
460mhz*0.79~363mhz
=> [email protected] consumes as much power as [email protected] (Stock)
I'm wondering if anyone's undervolted and to what values.
I'm also wondering waht the deafult values are and if they change per kernel.
Is there a way to disable SetCPUs undervolting settings?
Has anyone improved battery life with profiles? On the Eris this was the only way to get usable battery life.
Or not. I gave up undervolting after I actually compared battery life at stock values vs undervolted (on my old phone, sgs4g) and discovered it does nothing for battery life.
Edit: undervolting "might" marginally increase standby battery life, but considering how good this phone already does... it certainly won't increase actual screen on usage.
Sent from my Galaxy Nexus using xda premium
Depends how low you under volt. Got more battery life, maybe about an hour, after finding optimal battery life on my gfs Gnex.
If you don't under volt correctly, of course it won't improve battery life.
From my sexy white, Nocturnaled HTC One X
If you're not overly comfortable with undervolting, then using one of the many kernels with Smart Reflex will do a mild undervolt for you. If you are comfortable, then the only way to find numbers good for your phone is to try and test. I tweaked mine down to the point that I was occasionally getting hot boots when the screen was off and media was playing. Tweaking the numbers back up added the needed stability. Even little things like kernel or ROM revisions can change what voltage is or isn't stable. Another example is that when I updated my Jellybro CM10 version the other night, along with updating leankernel from 4.1.0exp3 to 4.2.0, I had to increase a few of my voltages to avoid hot boots.
Just for example numbers, here are mine:
Code:
1350MHz -- 1200mV
1200MHz -- 1150mV
920MHz -- 1050mV
700MHz -- 950mV
350MHz -- 825mV
These numbers will vary from device to device and even between ROM/kernel combinations, so don't use them as hard fact.
Thanks. On a phone like this it might not make a huge difference but on the Eris (Where stock battery life could sometimes be 6 hours if you actually used your phone) an undervolted kernel with setcpu could turn those 6 ours into 48.
Thanks Cilraaz, I'll try those voltages out and benchmark a bit to see if they're stable for my system.
Two things I can say for sure:
1. you will have very limit battery gain by undervolting with Gnex, no matter how low you try.
2. undervolting will bring some stable issue if you get too low, like lose signal and reboot.
I am using Kernel Franco GPU 384 Stock rom on my 4.1.1 and did undervolting
Current configuration:
384Mhz
950mv
------------
729Mhz
1050mv
-----------
1036mhz
1125mv
----------
1228mhz
1275mv
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I did not change the frequencies of overclocking, because I'm not using them.
I felt an improvement in battery consumption unless the unit is heating up.
Just curious - what kind of profiles are you using? I have a "Screen off" that's 350min and 700max. I figure that's fast enough f someone calls me.
I've read many times undervolting isn't worth it.
Hungry Man said:
Just curious - what kind of profiles are you using? I have a "Screen off" that's 350min and 700max. I figure that's fast enough f someone calls me.
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I'm using the following with SetCPU: default (1350MHz-350MHz), charging, CPU temp > 64, and battery < 35%.
If you're using a kernel and governor that support hotplug, then you likely don't want to use a screen off profile. The combination of the two can tend to cause sleep-of-death or hot boots.
I Am Marino said:
I've read many times undervolting isn't worth it.
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Click to collapse
Most people don't want to spend the time to do it right.
I'm actually not used to the new kernels. I haven't messed with my eris in about a year and back them there was "smartass, on demand, performance," and some other one that clocked down instead of up
Can you explain th escreen off profile causing issues? I don't even know what hotplug is lol I've been out of Android for a long time.
Hungry Man said:
Can you explain th escreen off profile causing issues? I don't even know what hotplug is lol I've been out of Android for a long time.
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Hotplug disables one of the CPU cores when the screen is off. Some governors, like hotplugx, will also attempt to disable a CPU core during periods of low CPU usage. For some reason, this combined with a screen off profile can cause some problems. I assume it's because of the "screen-off-max-freq" that Imoseyon mentions in the quote below.
Personally, I prefer the interactivex governor with leankernel by Imoseyon. From his kernel thread:
With interactiveX V2 (for gnexus), things are a bit different, since gnexus has built-in support for screen-off-max-freq for all its governors. I took the new interactive code in gnexus, added early_suspend support (screen off/on trigger), and then added logic to the code so the governor uses the phone's built-in hotplugging capability to turn off cpu1 when screen is off (and then turn it back on when screen comes back on). Cpu1 goes offline entirely - no idle, no sleep.
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I think undervolting helps - my phone is running 728 - 1228 using the interactive governor, with voltages of 600 mV, 700 mV, and 800 mV (728 MHz, 1036 MHz, 1228 MHz respectively) and I haven't had any issues so far. I know there are some reports that say undervolting doesn't help much, but those are when people undervolt by like 50 mV, whereas here I'm going like 400 mV under lol. (Yes, smart reflex is off).
Thanks Cilraaz. Good to know.
So turning the screen-off profile could improve things? Honestly, my system does fine at 350mhz with screen off. Turning a core entirely off would probably help though.
If I use hotplugx governor that would disable one core when the screens off, right?
Hungry Man said:
If I use hotplugx governor that would disable one core when the screens off, right?
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Click to collapse
Hotplugx will disable a core when the screen is off or when there is low system load. Depending on your kernel/governor choice, other governors may do it also. On leankernel, for instance, interactivex will disable a core when the screen is off, but not on low system load.
Ok, thank you.
I haven't done any comparisons of before/ after since I undervolted/ underclocked first thing. But I was browsing for hours while listening to music while talking to a friend with GTalk. talked for about 1.5 hours with someone, Left it on overnight (10 hours), woke up, used it to talk (voice to text) to someone via GTalk, and it's 3:25PM right now and I still have a fair amount of battery life left.
I'd heard mixed things about the battery on this so I'm happy.
My voltages:
1650: 1300
1520: 1250
1350: 1175:
1200: 1125
920: 1000
700: 925
350: 900
I stress tested each one without a crash.
I've been playing around with undervolting my Epic 4G with SetCPU and Voltage Control and have noticed that it does not crash if I force it to operate at one frequency -- apparently it is the switching from frequency to frequency at too low a voltage that crashes it. But what I'm seeing seems absurd -- I can overclock to 1200 MHz and set voltage to the 600 mV minimum and run just fine, so long as set the minimum to 1200 MHz as well.
I've run benchmarks with SetCPU and it definitely is running faster at the 1200 MHz setting. I am wondering if the 600 mV is "real" or if perhaps SetCPU and Voltage Control are misreporting what the CPU is actually running at.
I would think that half voltage would result in one quarter the power consumption, but I have not had a good opportunity to observe its battery life yet.