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.
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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)
Hi, i’m using the Franco’s Kernel and with the Franco’s kernel updater i’ve lowered the current of frequency 1305Mhz to 1250mV (the same current of the frequency 1228MHz). Also the question is, now with frequency 1305Mhz or 1228Mhz should the battery consumption the same or not?
Thank you
I don't think they will use the same current. mV is voltage and is not the current. Current is Amps. And if I am not mistaken although you are using the same voltage for both frequencies 1305Mhz will use more amps (current) hence use more energy, resulting in draining the battery quicker.
Although I could be wrong on that one.
I doubted about ampere me too, hence what's the aim changing voltage in the Kernel?
Inviato dal mio Galaxy Nexus usando Tapatalk
So that each frequency drain less juice then by default. But honestly I dont undervolt my frequencies, its fine the way franco's autocalibrate them.
So you lowered 1305MHz voltage to match the 1228MHz voltage at 1250mV. At an equal voltage, higher frequencies will use slightly more power. However, 1305MHz at 1250mV will use less power than 1305MHz at whatever default was. So undervolting will lead to some power savings, though they're extremely hard to measure.
If you're not overly familiar with undervolting, then using a kernel with Smart Reflex will do a good enough job of undervolting. It uses a moderate undervolt. Most people could lower the settings a bit below what Smart Reflex sets the voltage to, but the Smart Reflex settings tend to be stable.
For instance, I messed around with my phone and I'm running the following (using leankernel):
Code:
MHz - SR mV - Manual mV
1350 - 1250 - 1200
1200 - 1240 - 1150
920 - 1100 - 1075
700 - 1020 - 1000
350 - 840 - 825
You can see that I'm only nominally under Smart Reflex's values. I just like tweaking my phone as much as possible.
I'm not sure if Franco's kernel uses Smart Reflex or not. If it does, however, you could always allow SR to handle your undervolting so that you're sure to get a lower-than-stock-while-still-stable voltage.
thanks for your opinion!
A full charge, use of high frequency to 1900 MHZ CPU, but with power slowly become low, decreases in the CPU frequency even in the case of full load, the frequency of the CPU can't reach the highest, even down to the minimum 204 MHZ. Turn off after two core CPU, up to 1900 MHZ. What reason is this? Seems related to indoor temperature? Or loss battery? My system is Los14.1
Thank you, I hope someone can help me！
same problem but have no idea , really boring.
Same problem with my Pixel C. I could not find a solution yet.