Root Underclocking and Battery Issues

[Fordaz]

So I defected from iPhone a fewweeks ago to the HTC Desire, and was impressed with the Android OS. However, the battery life seems to be lacking in longevity somewhat.

For the first week, I put it down to overuse (new toy and all), but now I've been using it for about three weeks, and no more than I used my old 3GS, but the battery is still on it's last legs after about 8-10 hours off the charger, whereas my iPhone would have about 40% of the juice remaining.

I tried task killers, but this seemed to make no difference (and after reading some reviews about the Froyo OS making task killers redundant, I removed it).

A long-time droid user at work told me to "root" my phone and underclock my CPU, since the Desire has a power-hungry and totally unnecessary 1Ghz CPU.

I was just wondering from those of you who have rooted your Desire, did you notice a battery life extension from doing so? How much power can I realistically save by doing this?

 

[SUroot]

I wouldn't say 1GHz is unnecessary. But it is hungry. You can use an app called Set CPU if you root which you can set on battery profiles. For example, if the battery goes under 80%, you can set your CPU to 921Mhz, which will use less battery. You can stagger. Also you can set the scaling to "on demand" which helps to limit CPU usage that isn't required. You can increase your battery life by 20-50% Maybe more, depending how strict you are.

 

[FelixofMars]

Dan I really want to try the set CPU app at some point, my battery seems okay at the moment but I am interested to see what difference underclocking makes when the phone is idle. Do you think it makes a massive difference to the longevity I think I get roughly 35-40 hours on a full charge now with moderate use.

 

[SUroot]

I think the savings on battery differ depending on how much you are already saving. with set cpu, you can set the CPU to run at a maximum of 245Mhz if the screen is off.

Its worth a try if nothing else.

 

[Rahvel]

So I defected from iPhone a fewweeks ago to the HTC Desire, and was impressed with the Android OS. However, the battery life seems to be lacking in longevity somewhat.

For the first week, I put it down to overuse (new toy and all), but now I've been using it for about three weeks, and no more than I used my old 3GS, but the battery is still on it's last legs after about 8-10 hours off the charger, whereas my iPhone would have about 40% of the juice remaining.

I tried task killers, but this seemed to make no difference (and after reading some reviews about the Froyo OS making task killers redundant, I removed it).

A long-time droid user at work told me to "root" my phone and underclock my CPU, since the Desire has a power-hungry and totally unnecessary 1Ghz CPU.

I was just wondering from those of you who have rooted your Desire, did you notice a battery life extension from doing so? How much power can I realistically save by doing this?

There's a "trick" you can use to improve your battery life by an impressive amount. I'm not sure how it goes over linking to XDA forums from here but Official response from HTC RE: How to double battery Life (WORKS!) + 2nd Reply - xda-developers

This really helped me, although it's imperfect though because you have to repeat the trick once a week to keep it from reverting to its old lifespan.

 

[ianramsden87]

I just like to say that the SetCPU thing works so well it's unbelievable

currently sitting at 87% charge and my phone has been on for 6 hours.

I'm on the opendesire froyo ROM.
I have the 2nd latest radio updated.
I have setCPU to optimised but also have a profile setup to underlock the processor when the screen is off.

Usage today so far has been a few text messages/30 mins listening to MP3's on the way to work.

 

[SUroot]

It is amazing

 

[anoniemouse]

Been thinking of trying set cpu myself, but as i frequently get up to 4 days between charges normally it seems hardly worth it.

 

[SUroot]

Been thinking of trying set cpu myself, but as i frequently get up to 4 days between charges normally it seems hardly worth it.

It works the other way too, if you have an overclock Kernel, you can use it to up the CPU clock.

 

[anoniemouse]

It works the other way too, if you have an overclock Kernel, you can use it to up the CPU clock.

This is true, but although i would be interested in how high it could be pushed i would keep mine as stock.
I can see a good advantage in under clocking & getting more longevity out of the chip.

 

[ajanu]

Underclocking seems to be helping my battery life.

I have overclocked to ~1100 and ~1300 and I can't tell the difference in speed. Im underclocked to 768 right now with no speed problems.

I have noticed some slowdowns if I set the advanced powersave bias too high. 100 worked fine, trying 250 now.

 

[SUroot]

This is true, but although i would be interested in how high it could be pushed i would keep mine as stock.
I can see a good advantage in under clocking & getting more longevity out of the chip.

Richard Trip (DeFroSt developer) has managed to use his kernel to undervolt. He can get the same 998Mhz Clock speed using significantly less voltage than the HTC kernel.

In Tandem, he has produced a kernel which uses the same voltage as the HTC 998Mhz Kernel, while clocking it to 1305Mhz. I can get 1855 out of this rom on quadrant. I use the same battery as if I was on a Stock HTC Kernel, and the same voltage = no extra cpu degradation (from power at least).

Its super stable and super quick.

 

[ajanu]

Do you notice the extra speed with the 1305mhz? Maybe I don't push the phone hard enough but I couldn't tell the difference.

 

[anoniemouse]

Richard Trip (DeFroSt developer) has managed to use his kernel to undervolt. He can get the same 998Mhz Clock speed using significantly less voltage than the HTC kernel.

In Tandem, he has produced a kernel which uses the same voltage as the HTC 998Mhz Kernel, while clocking it to 1305Mhz. I can get 1855 out of this rom on quadrant. I use the same battery as if I was on a Stock HTC Kernel, and the same voltage = no extra cpu degradation (from power at least).

Its super stable and super quick.

Looks like i may have found my next rom to try, nothing like more power for no extra cpu degradation.

 

[SUroot]

Do you notice the extra speed with the 1305mhz? Maybe I don't push the phone hard enough but I couldn't tell the difference.

It depends what I'm doing. Normal web browsing etc, no. I just find it snappy in general. basically all the little things that are slightly faster all add up to be a huge benefit for me. I guess its all down to how you use your phone.

 

[SUroot]

Looks like i may have found my next rom to try, nothing like more power for no extra cpu degradation.

Its worth a try. May be worth getting used to LauncherPro if you're not already though, because its an N1 port, there is no sense or HTC apps at all.

It uses stock Email, messaging, Calendar, browser.

I didnt like the messaging app at first but I really like it now.

The browser still looks odd to me with the silver address bar and orange progress bar. Once I used the Cyanogen mod settings to change the Android status bar from Silver, its not too much to look at now.

The keyboard I created myself on gimpsta.

 

[universaljoint]

Just want to say that I agree 100% with those who have recommended underclocking with SetCPU as a way to extend battery life. I was getting quite frustrated with my Desire -- sometimes was below 50% before noon, and that was with auto-sync, GPS, and bluetooth off. Some of this may have been due to a bad app or idiosyncrasies of the custom ROM I was running, but whatever the reason, it was unacceptable.

Anyway, with SetCPU set to throttle my processor to minimum when the screen was off, and underclocking to ~800MHZ when it wasn't, I ran from 7AM-9PM and still had more than 70% of the battery remaining.

Performance-wise, I don't think I saw any difference in the Sense UI's responsiveness compared to running the phone at full speed. Although it is nice to have 1GHz under the hood when it is needed, I'm thinking I'll rarely have any reason to run it there, as the battery savings are way more useful than the performance boost, if there even is one.

If you're lamenting that you might need a second battery just to make it through the day -- do yourself a favour -- spend the $2 on SetCPU instead. It really does make a huge difference.

 

[SUroot]

Theres no performance boost with set cpu, unless you have a custom rom that uses a custom kernel to overclock.