Database Users

SetCPU and your settings?

I have a low end phone so I'm not used to so much increments of speed. I'm used to just having 2xx,4xx,6xx,8xxx instead of 2xx - 1600 so what settings do you guys have that is best for battery life and/or performance.
Appreciate it if you guys post your setCPU settings

1400 interactive - most my xoom can handle
Profile to cut back to 1000 at 35.2 degrees c - keep my oc'ed cpu from overheating hopefully
Profile to cut back to 456 when screen off - save battery

Mr Bland said:
1400 interactive - most my xoom can handle
Profile to cut back to 1000 at 35.2 degrees c - keep my oc'ed cpu from overheating hopefully
Profile to cut back to 456 when screen off - save battery
Click to expand...
Click to collapse
thanks for posting
seems like I have a good xoom because mine can run at 1600 stable

SetCPU Undervolting for Atrix

I understand there are numerous posts in various forums regarding under volting however, none of them relate to the Atrix!
The idea of this thread is to gather enough data that can enable us regular users of the Atrix, to safely and effectively undervolt our CPU's to enable maximum battery life.
I was wondering if you guys and gals would be willing to post what is working for you. I simply lowered mine -75mV for all frequencies on the list in SetCPU and it seems to have given me an extra boost in battery life by about one to two hours.
If you don't have the latest version of SetCPU: buy it off the market or search the forums for it and download it off here.

There's a thread in general from a week ago with some comments on undervolting. Also, in Faux's OC kernel thread there's quite a few posts later on (after he updated it to enable undervolting) with people posting their undervolting tests/settings.
As for me, I just put -50 for all and it's been stable.

People aren't going to waste time searching through the aforementioned posts or threads you've listed. I simply want it easier for people to click on one thread with the specific purpose of undervolting.

rdubyah said:
People aren't going to waste time searching through the aforementioned posts or threads you've listed. I simply want it easier for people to click on one thread with the specific purpose of undervolting.
Click to expand...
Click to collapse
Understood, but faux's kernel is thread is pretty active. Also , as obviously see yourself, the other Undervolting thread (which had the same purpose as this one) has already dropped off the radar (aka out of the first page) which will very likely be the same fate as this thread unless you're bumping it yourself every couple hours or it picks up steam. IMO it would have been easier build on the original undervolting thread so there's more info in a singular thread to build momentum on and keep it near the top.

mysticdrew said:
Understood, but faux's kernel is thread is pretty active. Also , as obviously see yourself, the other Undervolting thread (which had the same purpose as this one) has already dropped off the radar (aka out of the first page) which will very likely be the same fate as this thread unless you're bumping it yourself every couple hours or it picks up steam. IMO it would have been easier build on the original undervolting thread so there's more info in a singular thread to build momentum on and keep it near the top.
Click to expand...
Click to collapse
I cant post on fauxs thread yet. Just building some juice here. Agreed there is the right place for this discussion.
Sent from my MB860 using Tapatalk

where in SetCPU is the option to undervolt??

Like I mentioned in my original post, search the forums for the latest version of SetCPU or purchase it off the market.

Ive got every frequency at -500 except for 1100. Which i have at -100.
Sent from my MB860 using XDA App

Weese said:
Ive got every frequency at -500 except for 1100. Which i have at -100.
Sent from my MB860 using XDA App
Click to expand...
Click to collapse
edit: wow you can go -500 and be stable!
right now im stable at -100 -100 -75 -75 -75 -75 -75

I had everything at -50 and my phone was stable until I used my GPS and it rebooted. I now I have everything at -25. So far so good.
Sent from my MB860 using XDA App

Weese said:
Ive got every frequency at -500 except for 1100. Which i have at -100.
Sent from my MB860 using XDA App
Click to expand...
Click to collapse
I find it hard to believe that your phone is stable at those undervoltage settings but if that is the case (no random reboots) that's pretty impressive.

Weese said:
Ive got every frequency at -500 except for 1100. Which i have at -100.
Sent from my MB860 using XDA App
Click to expand...
Click to collapse
I'm betting typo...

You can manually make every frequency to -500 or some other crazy settings, and sometimes it will crash and sometimes not. The thing is, the Tegra2 chip only recognizes and performs less than 100mHz change in-between each step/frequency. So is the different between 2 frequencies is greater than 100, it will still only recognize and use only 100mHz. So even if you are able to set every frequency ridiculously low, the chip is not running at those voltages. Read more about this on Faux123's Kernel thread to understand it fully, I'm just regurgitating it. Hope this helps.

I think I have the newest version of set cpu 2.2.4 and I can't find the volt tab am I missing something is there a setting option I need to enable? I was using faux's kernel with ninja rom

TechRebel said:
I find it hard to believe that your phone is stable at those undervoltage settings but if that is the case (no random reboots) that's pretty impressive.
Click to expand...
Click to collapse
isn't there an issue with faux kernel right now where if you go past -100 it still does -100 not that value you've input (i.e. if you put in -500 its still actually doing -100)

i've been running the following setup, on my second day without charging (only moderate use, gaming for about 45 minutes to an hour and a half plus using my phone as internet browser multiple times throughout the day, 5-6 widgets total. sitting at 18% left, and i'm on hour 30 something)
now, keep in mind this is also using the battery calibration app, ninja speed freak and faux's oc kernel.
-25
-30
-30
-50
-100
-100
-150
i've been averaging around 3000-3200 quadrants in the quadrant standard benchmark test, so needless to say i'm extremely satisfied with my settings.
also have custom profiles set up, if my screen is off i run at 608mhz max, 216 min. charging gets 1100 max 216 min, incall gets 216 max 216 min, battery less than 15% gets 608 max 216 min and battery<10% gets 456 max, 216 min.

Alcapone263 said:
i've been running the following setup, on my second day without charging (only moderate use, gaming for about 45 minutes to an hour and a half plus using my phone as internet browser multiple times throughout the day, 5-6 widgets total. sitting at 18% left, and i'm on hour 30 something)
now, keep in mind this is also using the battery calibration app, ninja speed freak and faux's oc kernel.
-25
-30
-30
-50
-100
-100
-150
i've been averaging around 3000-3200 quadrants in the quadrant standard benchmark test, so needless to say i'm extremely satisfied with my settings.
also have custom profiles set up, if my screen is off i run at 608mhz max, 216 min. charging gets 1100 max 216 min, incall gets 216 max 216 min, battery less than 15% gets 608 max 216 min and battery<10% gets 456 max, 216 min.
Click to expand...
Click to collapse
Been using these settings for 3 days and I can honestly say they're fantastic. I was getting 11-18 hours out of my Atrix with other ROM/Kernel/CPU settings; with this setup I get 30-40hours. Simply fantastic.
I'm a fairly light user, but I keep data/wifi on at all times (even screen off) syncing 3 exchange accounts (push); make about 10 mins of phone call in a day; surf slashdot/xda/engadget/etc once every hour or two; and watch 5-30mins of flash vids a day.
Only thing to note is that I had to adjust the UV on the lowest setting to -125 to avoid intermittent loss of WiFi connectivity.

Alcapone263 said:
i've been running the following setup, on my second day without charging (only moderate use, gaming for about 45 minutes to an hour and a half plus using my phone as internet browser multiple times throughout the day, 5-6 widgets total. sitting at 18% left, and i'm on hour 30 something)
now, keep in mind this is also using the battery calibration app, ninja speed freak and faux's oc kernel.
-25
-30
-30
-50
-100
-100
-150
i've been averaging around 3000-3200 quadrants in the quadrant standard benchmark test, so needless to say i'm extremely satisfied with my settings.
also have custom profiles set up, if my screen is off i run at 608mhz max, 216 min. charging gets 1100 max 216 min, incall gets 216 max 216 min, battery less than 15% gets 608 max 216 min and battery<10% gets 456 max, 216 min.
Click to expand...
Click to collapse
Are these voltage settings going from 1100MHz (-25) to 216Mhz (-150)?

crea78 said:
Are these voltage settings going from 1100MHz (-25) to 216Mhz (-150)?
Click to expand...
Click to collapse
Correct from highest to lowest, starting at 1100mhz.
Also, I may have just extended the battery life to 48~ hours last night by using these settings and using a combination of autostarts to stop non-essential processes from starting and titanium backup to freeze non-essential processes that seemed to start anyway.
Also note; when setting up the profiles in setCPU, make sure you get the priorities right; otherwise they can be fairly ineffective.

Alcapone263 said:
i've been running the following setup, on my second day without charging (only moderate use, gaming for about 45 minutes to an hour and a half plus using my phone as internet browser multiple times throughout the day, 5-6 widgets total. sitting at 18% left, and i'm on hour 30 something)
now, keep in mind this is also using the battery calibration app, ninja speed freak and faux's oc kernel.
-25
-30
-30
-50
-100
-100
-150
i've been averaging around 3000-3200 quadrants in the quadrant standard benchmark test, so needless to say i'm extremely satisfied with my settings.
also have custom profiles set up, if my screen is off i run at 608mhz max, 216 min. charging gets 1100 max 216 min, incall gets 216 max 216 min, battery less than 15% gets 608 max 216 min and battery<10% gets 456 max, 216 min.
Click to expand...
Click to collapse
Gonna give you mad props for this. Doing great things to extend battery life.
Sent from my MB860 using Tapatalk

Does cpu frequency affects battery life?

The question is simple, the higer the freq. the more battery consumption? i am asking because i cannot see any difference from 1.4GHZ to 1.0GHZ, the battery consumption is the same under oxygen and francos kernels. i would be grateful if the experts would give us some advise or their opionion. I know it is subjective but i would like a second opinion.
Thanks alot guys

If you look with any cpu spy app, you cab see on what clock the processor is used. I mainly have it the lowest and sometimes higher. When you change the max, it should still automatically choose what clock is used, so battery should last as much as before, if not used in high clock.
Sent from my Huawei u8800 using XDA App

Invicta said:
The question is simple, the higer the freq. the more battery consumption? i am asking because i cannot see any difference from 1.4GHZ to 1.0GHZ, the battery consumption is the same under oxygen and francos kernels. i would be grateful if the experts would give us some advise or their opionion. I know it is subjective but i would like a second opinion.
Thanks alot guys
Click to expand...
Click to collapse
Probably not much difference, when you overclock, think the cpu voltage remains the same as it is on 800mhz... And the highest cpu freq is rarely even at use...

Invicta said:
The question is simple, the higer the freq. the more battery consumption? i am asking because i cannot see any difference from 1.4GHZ to 1.0GHZ, the battery consumption is the same under oxygen and francos kernels. i would be grateful if the experts would give us some advise or their opionion. I know it is subjective but i would like a second opinion.
Thanks alot guys
Click to expand...
Click to collapse
Well, thanks to most devoted users of U8800, we have somewhat better speed+battery life than stock also. To answer your question, yes depending on your activity the frequency have some impact, but overall shouldn't be huge in change, for example from .800 to 1.0GHz will not affect so much in daily use. However from .800 to 1.5GHz would make a somewhat huge gap difference. This doesn't mean it will drain faster if you do same activity as with .800 to 1.0GHz, for example check the watch, answer sms or few "entertainment" breaks. Only when using the phone over a longer period of time that's when you will notice the change of battery life with different frequency. Hope it clears up most hums and huhs for you. I am pretty sure some expert within this field will give a better explanation than me.
Bye~

higher freqs uses more energy, but lower uses less energy but do things slower (so energy consumption is longer). ALSO imo - if you set cpu to 1Ghz the lowest value so it always is 1ghz - it will not consume the same amount of energy if it's in idle mode - it's like your laptop - if cpu is working only in 4-7% of it's power - then the power consumption is lower no matter what freq - how do we know that? - because of heat - the more heat you get - the more energy was used. and when cpu is idle - it will not be hot.
So the answer is - if it saves then in VERY minimal amounts. But even so - i use min freq - 360mhz. it's good for me i do not get any lag so i use it.

I use the "Root System Tool Free", option CPU and I see the graphics of all clocks.
For ex. now at 245 mhz ->46%, at 368 ->10%, at 768 mhz ->18% .... and at 1612 mhz -> 1,8%, at 1804 mhz ->4,9%. Not very mutch use at 1804.
Oxygen-test-140911 + Franco.Kernel1709#1. Clock at 1804 Mhz by Menu-settings-cpu ... and smartassV2 (no profils).
The battery, I charge it all 24 hours. But I like my work... and testing things. When then will dead...I see...

ValenteL said:
I use the "Root System Tool Free", option CPU and I see the graphics of all clocks.
For ex. now at 245 mhz ->46%, at 368 ->10%, at 768 mhz ->18% .... and at 1612 mhz -> 1,8%, at 1804 mhz ->4,9%. Not very mutch use at 1804.
Oxygen-test-140911 + Franco.Kernel1709#1. Clock at 1804 Mhz by Menu-settings-cpu ... and smartassV2 (no profils).
The battery, I charge it all 24 hours. But I like my work... and testing things. When then will dead...I see...
Click to expand...
Click to collapse
cpu spy is more pretty, anyway all those apps just reads text file of cpu stat and that's it

Tommixoft said:
cpu spy is more pretty, anyway all those apps just reads text file of cpu stat and that's it
Click to expand...
Click to collapse
Thanks
But I like more the Root System Tool, because has also a Linux Console. I use it when I want make some cmd's Linux in #. I don't like the Terminal Emulator.

Well, there is a "catch" somewhere in there. The frequency does indeed affects the power consumption of the CPU and greatly at that too! But the thing is, your CPU is not the worst enemy of your battery life. Even though CPU consumes more power in higher frequencies, it still can not compete with what your screen LEDs or your GSM module or your GPS chip consumes leisurely. So, if you're looking at the overall picture -meaning if you're wondering if it will affect how long you'll be able to use your battery in your phone- the answer is, "yes but not so much". Especially if you're switching the CPU frequency based on the demand (like using smartass or on-demand governors)
Here are the thing that sucks your batteries life juice like a vampire :
Your Screen (especially background LEDs)
GSM module (talking, using GPRS/Edge/3G network communication)
GPS chip
Wireless module (this also includes Bluetooth, even though it does not consume as much as Wireless network access but everything is relative -think about playing music through A2DP headphones compared to having your wireless network active but not using it much-)
(oh yes, I love to use lots of parenthesis -and even this hyphenation thingy- )
Correct me if I'm wrong about anything by the way ..
Regards ..

I did some experiments with a msm8250 a while back and there's a graph here:
http://forum.xda-developers.com/showpost.php?p=14324649&postcount=3786
msm7x30 should be fairly similar though the graph is probably shallower since it's a smaller process size.
The CPU uses no power when it's not in use, even with the display on, the CPU is powered down completely when idle (power collapse).

Possible fix for random reboots on Gingerbread

Here are my current stable settings:
SetCPU
Min: 100mhz
Max: 1000mhz
Governor: Ondemand
Profile: Screen Off
--Min: 100mhz
--Max: 200mhz
--Priority: 100
--Governor: Ondemand
Tegrak:
Governor: Ondemand
Scaling: 100-1000mhz
Optimization:
--200mhz Core Voltage: 1025mv
--100mhz Core Voltage: 925mv
Both SetCPU and Tegrak are running side by side.
No random reboots for over a week.
Battery should last between 20-25 hours with normal usage.
Certain phones might need a higher voltage, you may need to do some experimenting to get things stable.
Old text
Anyone experiencing random reboots should try using SetCPU or Tegrak to set the CPU to 1000mhz-1000mhz instead of 100mhz-1000mhz.
I was previously getting 3-4 reboots per day. I set my CPU to 1000mhz-1000mhz using Tegrak four days ago and have not had a single reboot since.
Sure, my battery only lasts about 10 hours vs 20 or so, but at least I can rely on my phone.
Of course I could just be lucky, and who knows it might just randomly reboot any time now.. So, obviously there is no guarantee it will work for anyone else.
Just as a note I also tried 200-1000 and 400-1000, but still had random reboots every few hours.
I am currently testing 200mhz-200mhz with the screen off and 1000mhz-1000mhz with the screen on using SetCPU. I will update this thread in a few days or if it randomly reboots.
Update: 200mhz during screen off causes the phone to not wake up (happened three times). I'm currently testing 400mhz.
Update 2: I got a random reboot last night while asleep using 400mhz. I will see if it continues.
Update 3: Got another reboot at 400mhz. I am now testing 100mhz-1000mhz at 1.275v Core and 1.100v Internal for all frequencies, this should rule out any voltage issues.
Update 4: Made a spreadsheet with my findings, it does not seem to be a voltage issue.
Update 5: Scratch that, I have been using a [email protected] screen off profile for the last 20h... No black screen of death or random reboots. Next up is [email protected]
Update 6: [email protected] is unstable, rebooted after 3 hours. Testing [email protected], 6 hours in and no reboots yet.
Update 7: [email protected] seems to be stable, 24 hours and no reboots yet.
Old text
Click to expand...
Click to collapse
Here is a spreadsheet of my current findings.

My random reboots always came while in deep sleep so this will not work for me. I switched back to a EG22 ROM and get no reboots.
Sent from my SPH-D700 using XDA App

kennyglass123 said:
My random reboots always came while in deep sleep so this will not work for me. I switched back to a EG22 ROM and get no reboots.
Sent from my SPH-D700 using XDA App
Click to expand...
Click to collapse
Same here, but for some odd reason this (seems to have) fixed it for me. Although, on EG22 I also got a lot of random reboots, so maybe I have a different issue.
I did not get reboots on ED12, EE03, or EF02..
EG22, EH06, and EH17 randomly reboot for me.

I thought it might be similiar to the sleep of death phones would get going from 100 Mhz to deep sleep and also tried boosting to 200 Mhz on EH17 but it didn't help. It may be related and your discovery may aid Devs in fixing the problem If it is still there when source is released.
Sent from my SPH-D700 using XDA App

I think the problem lies in the voltage settings that deep sleep runs on, like in tegrak overclock if the internal voltage is too low the phone will reboot.
Maybe some samsung devs tried lowering the voltages in deep sleep to optimize battery life but only tested it for like a couple hours and didn't notice it.
Are there any ways to edit these values somewhere in the kernel because I know tegrak nor setcpu can do anything to deep sleep.
Sent from my SPH-D700 using xda premium

xopher.hunter said:
I think the problem lies in the voltage settings that deep sleep runs on, like in tegrak overclock if the internal voltage is too low the phone will reboot.
Maybe some samsung devs tried lowering the voltages in deep sleep to optimize battery life but only tested it for like a couple hours and didn't notice it.
Are there any ways to edit these values somewhere in the kernel because I know tegrak nor setcpu can do anything to deep sleep.
Sent from my SPH-D700 using xda premium
Click to expand...
Click to collapse
+1 That's what I think.

That would explain why my phone never reboots with the screen on.

I think we may be onto something in this thread.
Sent from my SPH-D700 using XDA App

Agreed. My phone has always randomly rebooted when the screen is off. I set the minimum to 400 Mhz as well. Will let you know what goes down.

Someone should point the SamSprint devs to this thread lol. That would be amusing if it was in fact the problem/solution to random reboots.
Sent from my SPH-D700 using xda premium

Ok, so far 400mhz screen off has been stable, 12:56 on battery, and 1:01 screen on time.
I noticed something.. Here is what CPU Spy says:
1000mhz: 00:55:03
400mhz: 1:35:09
Deep Sleep: 9:22:42
I reset the stats once, which is why 1000mhz is 6 min different from the screen on time.
The phone was asleep for 11:55, but it was only in deep sleep for 9:22, what this tells me is when the screen is off and the phone needs to "do something" (I have Skype open 24/7, and 3 accounts in k9)it will jump up to 400mhz (or normally, anywhere between 100-1000mhz) for a time until it is finished, and then drop back into deep sleep.
It might be worth a try to bump up the voltage for 100mhz and 200mhz and see if that helps anything.

So I played around with the clock settings a bit in the last 24 hours. Here's what I've found:
If I set the minimum to 200Mhz or lower, and leave the phone alone, it continues to have random reboots. With the minimum set to 400Mhz, it sleeps fine all day long. I also tried adding in the profile to enable a minimum and maximum of 200Mhz when the screen is off. In the 4 hours that was set I didn't get any random reboots, but when I went to wake the phone up, it rebooted. And with the min/max set to 200 on the screen sleep profile on, if the screen turns off and I try to turn it back on, it would reboot. What I found to work best is if the screen off profile min and max is set to 400, and then the mains are at 200 min and 1000 max, it runs (so far for me) with out any reboots and the phone will wake up like normal again. This has been good for the last 10 hours, so I will continue to let it simmer and will see how it goes.
So I know that the 100Mhz and 200Mhz states were active and working in Froyo. If they aren't working correctly here, could it possibly be because Samsung set the voltages of those two freq's too low in GB?

when looking at the voltage settings for 400, they are lower in GB versus Froyo by -50. maybe thats causing the issue?

If its really this simple as far as clock and voltage how the hell does Samsung not find that.
Sent from my SPH-D700 using xda premium

What software are you guys using to adjust these settings, SetCPU? Is there a free alternative that does the same thing? Since I've been reading this thread, my phone has slept to death several times (EH06) - I'm hoping this solves it.

ss4rob said:
What software are you guys using to adjust these settings, SetCPU? Is there a free alternative that does the same thing? Since I've been reading this thread, my phone has slept to death several times (EH06) - I'm hoping this solves it.
Click to expand...
Click to collapse
SetCPU is free for xda members
Sent from my SPH-D700 using Tapatalk

I recently downgraded to EC05 due to the reboots, but left the EH17 Modem.
I still get reboots, and now believe the reboots are related to the modem, GPS issues, and general updating, as new e-mail notifications would sometimes be followed with an immediate reboot.
I'm gonna flash the EF02 Modem onto EH17 to see if it works, I have nothing to lose at this point as i'm returning my epic today. Stupid B and V dont work on my keyboard

radugb said:
So I played around with the clock settings a bit in the last 24 hours. Here's what I've found:
If I set the minimum to 200Mhz or lower, and leave the phone alone, it continues to have random reboots. With the minimum set to 400Mhz, it sleeps fine all day long. I also tried adding in the profile to enable a minimum and maximum of 200Mhz when the screen is off. In the 4 hours that was set I didn't get any random reboots, but when I went to wake the phone up, it rebooted. And with the min/max set to 200 on the screen sleep profile on, if the screen turns off and I try to turn it back on, it would reboot. What I found to work best is if the screen off profile min and max is set to 400, and then the mains are at 200 min and 1000 max, it runs (so far for me) with out any reboots and the phone will wake up like normal again. This has been good for the last 10 hours, so I will continue to let it simmer and will see how it goes.
So I know that the 100Mhz and 200Mhz states were active and working in Froyo. If they aren't working correctly here, could it possibly be because Samsung set the voltages of those two freq's too low in GB?
Click to expand...
Click to collapse
What scaling are you using?

This sounds more like a band-aid than a fix. Perhaps the system doesn't scale the clock speed properly when waking, and keeping the clock speed artificially high in sleep mode masks the problem.Not an ideal solution because it kills battery.

omair2005 said:
when looking at the voltage settings for 400, they are lower in GB versus Froyo by -50. maybe thats causing the issue?
Click to expand...
Click to collapse
Good catch. Here are the voltages on EH06 (as reported by Tegrak):
1000mhz
Core Voltage: 1275mv
Internal Voltage: 1100mv
800mhz
Core Voltage: 1200mv
Internal Voltage: 1100mv
400mhz
Core Voltage: 1050mv
Internal Voltage: 1100mv
200mhz
Core Voltage: 950mv
Internal Voltage: 1100mv
100mhz
Core Voltage: 950mv
Internal Voltage: 1000mv
Could someone list out the stock voltages on EC05?
Lord-Anubis said:
I recently downgraded to EC05 due to the reboots, but left the EH17 Modem.
I still get reboots, and now believe the reboots are related to the modem, GPS issues, and general updating, as new e-mail notifications would sometimes be followed with an immediate reboot.
I'm gonna flash the EF02 Modem onto EH17 to see if it works, I have nothing to lose at this point as i'm returning my epic today. Stupid B and V dont work on my keyboard
Click to expand...
Click to collapse
That is what I thought at first... But then I tried the EF02, and EE03 modems and still experienced reboots (I am currently on the EE03 modem).
poit said:
This sounds more like a band-aid than a fix. Perhaps the system doesn't scale the clock speed properly when waking, and keeping the clock speed artificially high in sleep mode masks the problem.Not an ideal solution because it kills battery.
Click to expand...
Click to collapse
While this is true (for now) it could lead to a more viable fix. If the voltage actually is lower in GB, that could be at least part of the problem.

Undervolting a Xoom - battery results included

I haven't been able to find any info on undervolting the Xoom, so have started this thread in the hope that some may find it beneficial.
What is undervolting?
It basically involves reducing the amount of electrical voltage running through the CPU. It does not affect the speed of the CPU at all, just the amount of power that it uses. The stock configuration of CPUs usually has a fairly high voltage, to cater for the fact that CPUs are not exactly identical.
Why undervolt?
Reduce power consumption, and therefore increase battery life.
Why not undervolt?
Can affect stability, and there is a small risk of damage to your device.
Disclaimer: Undervolting, like overclocking, does have the potential to damage your device. It's very rare, but not unheard of. I've never had a problem, but you may. Good luck, and don't blame me.
My config:
Model: MZ601 Xoom
Kernel: Tiamat Xoom v2.1.0
Undervolting software: SetCPU 2.2.4
My voltages before UV:
MHz mV
216 770
312 770
456 825
608 900
760 975
816 1000
912 1050
1000 1100
1200 1150
1408 1250
1504 1325
1600 1400
1704 1400​
So after doing a bit of testing, I've found that I can lower my voltages noticeably throughout the range, reducing the amount of power my Xoom uses, and prolonging my battery.
My UV voltages:
MHz mV
216 770
312 770
456 775
608 825
760 875
816 925
912 975
1000 1000
1200 1075
1408 1125
1504 1175
1600 1250
1704 1325​​
Notes:
It is not possible to UV any less than 770 mV (with the kernel I'm using anyway).
Given that the mV for the 456 CPU frequency is so similar to 216, I set my minimum clock frequency to 456, which makes the device more responsive.
So, you may want to try these voltages, and see how they work for you.
To test: (Instructions for SetCPU)
Set your min & max speeds to the same frequency, for example 456.
Set the voltage of the 456 frequency to an amount lower that the current amount, for example 775. (It's generally best to adjust your voltage down only 25mv at a time.)
Perform a "Stress Test", for at least about 5 seconds.
If the device locks up or reboots, the mV is too low - try a higher mV.
Once you've found the optimal voltage for that frequency, move onto the next one, for example 608, then 760, etc.
If your device locks up or freezes during testing, you can force a reboot by holding down the Volume Up button, and the Power button.
The voltages I've used above may work for you, or you may have to increase them a little on your device. You may also get better voltages than me - if so, please post your results.

Battery test results
Performed some battery performance testing by doing the following steps:
1. Set the screen to not turn off, and brightness to 10% (screen needs to be on to keep the stress test running, and brightness low to minimise the battery drain of the screen, as that's not what we're testing).
2. Disabled all network connections (WiFi, Bluetooth, Data, GPS) to minimise battery drain by other factors.
3. Closed all other apps, and did not use the Xoom at all during the tests.
4. Charged Xoom to 100%.
5. Set CPU speed to 1504mhz using SetCPU (both min & max frequencies the same for accurate testing).
6. Unplugged the Xoom.
7. Ran "Stress Test" for 2 hours (give or take 20 seconds).
I performed the above steps for both stock voltage, and undervolted voltage. Results as follows:
1. For stock voltage (1325mV on Tiamit Tachi kernel), battery life went down to 62%.
2. For undervolted voltage (1175mV, which is nice & stable for me), battery life went down to 72%.
Findings:
I was expecting battery savings, but not quite this much.
Standard voltage (at 1504mhz) at this CPU load, drains at about 19% per hour.
UV voltage at this CPU load, drains at about 14% per hour.
Standard voltage at this CPU load, the Xoom would drain battery entirely after about 5.26 hours.
UV voltage at this CPU load, the Xoom would drain battery entirely after about 7.14 hours.
In addition to the battery savings, the Xoom was only slightly warm after the UV tests, but very warm after the standard voltage tests. (Standard voltage test was performed first.)
Note: For general usage (email, browsing, basic apps & widgets), the CPU is not as heavily used. But in situations where the CPU is heavily used (such as intensive games), these results show there is significant potential for battery savings.

super nice tips. Tq very much

126-608 -175
Others -150
This is my settings... no prob at all.

Would I use setcpu app or just use the Moray(in settings) or does it matter

rayhodge02 said:
Would I use setcpu app or just use the Moray(in settings) or does it matter
Click to expand...
Click to collapse
Not sure what the "Moray" is, but any tool capable of undervolting should be ok. I like and use SetCPU, but I've tried other tools on other devices in the past, and they did similar things.

nobody wants to share their result after trying?

Very good job, I try
Sent from my Xoom using xda premium

pls share ur best result

I try your results and they're unstable in function off the useful task, exemple impossible to play simple games.
That's all right just for basic tasks like navigation, music ...
Sent from my Xoom using xda premium

Hmm, your stress testing seems inaccurate.
I used your values and did a stress test at each frequency for around 10 seconds. No problem. But my xoom restarted just 5 mins later while I was surfing the net.
So I increased each frequency by 25-50 and it stayed stable since then.

for me i just underclock my xoom to 912mhz. it is almost as fast as 1ghz. and i save battery alot.

Gregus59 said:
I try your results and they're unstable in function off the useful task, exemple impossible to play simple games.
That's all right just for basic tasks like navigation, music ...
Sent from my Xoom using xda premium
Click to expand...
Click to collapse
Try bumping up the voltages a little bit at a time, until you find a stable setting. The settings I listed are what are stable for my Xoom (even intensive 3D games), but CPUs vary. What I get, others may not, and others may get better than me.

musashiken said:
Hmm, your stress testing seems inaccurate.
I used your values and did a stress test at each frequency for around 10 seconds. No problem. But my xoom restarted just 5 mins later while I was surfing the net.
So I increased each frequency by 25-50 and it stayed stable since then.
Click to expand...
Click to collapse
They're not 100%. The longer you stress test, the more likely the CPU is stable, but 10 seconds gives a general idea. If unstable, just do as you did, and increase by 25mv or so.

omnia1994 said:
126-608 -175
Others -150
This is my settings... no prob at all.
Click to expand...
Click to collapse
Can you confirm your mV values? -175 sounds like a big saving. Surely your mV is not less than the minimum 770?
What kernel are you using?

do some proper tests to establish how much extra time you will get from a fully charged batt.
i would think its perhaps a tiny bit at most...
the screen would take a huge amount of the batt, the processor would use only a small percentage, so surely cutting a small fraction off a couple of steppings is fairly pointless?

baron von bubba said:
do some proper tests to establish how much extra time you will get from a fully charged batt.
i would think its perhaps a tiny bit at most...
the screen would take a huge amount of the batt, the processor would use only a small percentage, so surely cutting a small fraction off a couple of steppings is fairly pointless?
Click to expand...
Click to collapse
1. It depends what you're using the device for. Games, for example, can use a lot of CPU, so undervolting in this instance, will definitely use noticeably less battery.
2. If CPU voltage throughput didn't make any difference, we'd all just run our devices at 1700mhz all the time.
3. With undervolting, I can run my Xoom at the same voltage at 456mhz, as it run at 216mhz. This means I set my minimum frequency to 456 instead, and for the same minimum battery consumption, my device is noticeably smoother.
If you want to know how much extra time you will get from a fully charged battery, YOU do some tests.

lindsaytheflint said:
Can you confirm your mV values? -175 sounds like a big saving. Surely your mV is not less than the minimum 770?
What kernel are you using?
Click to expand...
Click to collapse
Yes i m sure. Has been using these settings till now.. no prob at all. Using tiamat stock gpu kernal with moray rom

i agree that during low intensity operation the power savings are probably nearly negligible, but during CPU-intense usage it could save a bit.
I myself am not willing to leave my Xoom on full bore for a series of tests lasting 7-10 hours each just to quantify how much power undervolting can save under super extraordinary circumstances.
But even if the energy savings is an arguable benefit, the reduction in CPU temperature is not. That alone makes this worth doing, IMO.

Agree.. after setting it my xoom now has lower temp when playing it