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Task Killers Put to the Test, Do They Actually Extend Battery Life? As Expected, They Most Certainly Do Not

We have written a number of times about the idea that task killers on Android do not help battery, no matter what that carrier rep who sold you your new phone has told you. In general, most of us look at Android as a multi-tasking platform that likes to have activities in the background to make your phone perform faster and more efficiently. By constantly killing off apps, you are working against what the OS is trying to do, hence the reason task killers are evil.

On the flip side, there are Android users who continue to believe that task killers are helping their phone no matter what we or a variety of devs tell them. They are addicted to killing apps and have convinced themselves that it will only help out the battery technology from 1952 that is stuck in their phone.

To settle the argument once and for all, PCWorld took to their “labs” to test a handful of phones and decide once and for all if task killers will extend the life of your phone. The verdict? They won’t. 

According to their results, HTC phones saw upwards of 17 minutes of extra battery life with a task killer, but I think we can all guess why. Sense has more background syncs and tasks running than any other skin on the planet and probably could see some benefits to killing off tasks from time to time. Funny thing there, is the fact that in Sense 3.5, HTC built a task killer into the OS. The Bionic did not see a difference and maintained the same battery life it had without a task killer. The Galaxy S2 on the other hand, saw slightly worse battery life with a task killer.

So, as the Android dev community has been trying to tell you since the introduction Froyo, a task killer is not helping you. Stop using one to try and extend battery life, and get back to enjoying your phone.

Via:  PCWorld

Cheers Shawn!

  • Dbond

    only thing i use a task manager for is to free up memory for other tasks, kill the ones i dont use that auto starts on my phone, otherwise all my free memory gets used up and makes the phone sluggish as hell.  granted im still using a droid eris but still.  as for battery life, doesnt make much sense for it to save battery unless something is constantly syncing.  constantly having to reopen a program that you use all the time, that you have killed, is going to take more processing power and in turn drain your battery life.

  • Hardryv

    Well in any ‘tech scenario’ there is always more to the story… The real question about whether or not a task killer affects battery life on a given smartphone has to discussed more deeply.  First-off, what is the proposed collection of task-killer programs doing?  (killing all non-required tasks at continuously, at interval, and whenever an app doesn’t have focus?; killing all non-required tasks once when ordered to and then shutting down; there are many other scenarios I won’t even try and list).  And then what apps are being loaded before allowing the rest of that testing to proceed?

    I say that because here is something I can tell you free and clear.  If I run the camera, my battery life fades almost in real time.  I don’t know how savvy the developers behind that are / were.  I can’t rely on them to have closed down all of the meaty portions of that application.  Also gaming with sound… forget about it.  I got maybe 3 hours tops on my sensation unless it’s plugged in… and *even then* I’ve seen it eat faster than the cord can feed in power (i.e. system still shut down even though it was plugged in).

    I personally use DroidSpeed because it has a 1×1 widget that allows you to slam ‘now’ and then it’s over and done with.  You can say they don’t help, and maybe there’s a context you can find where they don’t, but try leaving you camera or a loud, detailed game on in the background and redo your testing.

    In an earlier life phase before I programmed software for a living I managed tech labs at Dell Computer, and I’ve been in each each role over 10 years now.  If your argument is that task-killing can’t help save power, I would propose to you something about Heisenberg Uncertainty Principle and your obviously silly assertion that systems which aren’t actually on are consuming more power than systems that stay on all the time.

    If they take virtually no space, eat up no CPU cycles, serve purposes other than mere power-savings, and hurt nothing… leave those of us who use them alone k thx.

  • I like having a task killer on both of my phones so I can kill off a stuck app manually.  I turn off auto-kill and just use it manually.  It is much faster than home/menu/settings/applications….

  • Chris Sandoval

    My moms Droid 2 had been acting up, I tried a hard reset, and rebooted. But nothing. She takes it to Verizon, they do a soft reset, and download her advanced task killer. -_- just made it worse.

  • thinking you need a task killer is like thinking you need a screen protector for gorilla glass.

  • Tomas Arroyo

    What task killer was used? I thought killing apps running in the background did save on battery life??? or was I wrong?

  • Anonymous

    Who needs task killers when I have the V6 Supercharger?

  • Lgreg64

    this says it make no big change so if you run one or not. i have one loaded but only use it when some program   gets start to act up.

  • Anonymous

    I honestly think task killers make a difference. I know everybody says they dont but i know 100% that on my droid charge (before they gave me an iphone 4s for free)  if i did the task killer the phone would stop lagging for a while

  • I dissagree with this.  I used a task killer to end my email client one morning (cause it was not acting right) and the phone (Droid Eris) lasted into the next afternoon (24+ hrs) and the batt was still over half.  Normally my phone goes 8-10 hrs and is at 25% or less. It was the weekend so I didn’t even need my email (not to be confused with gmail).

  • When I bought my OG Droid I was never told to use a task killer. However it was an app on a paper they gave me of recommended apps.

  • Anonymous

    One of the first things I removed after rooting my phone was the task killer app that it came with. Cleared up ram and battery lasted longer.

  • Anonymous

    It’s not that hard to go into running services and stop apps that you don’t want running… task killers blow by the way…

  • MattInPDX

    I used Task Killer on my OG Droid because it would speed it up by shutting down programs and freeing up memory.

  • Brett328

    I was one of the users plagued by multiple reboots on the Thunderbolt before the fix got pushed out by Verizon.   Installing a task killer an setting it up to kill agressively definitely slowed the reboots down to almost zero.  I’m sure it didnt help with battery life, but it kept my T-bolt up and running with virtually no reboots.

  • StormbladeX69

    I use ATK to kill an app when it has issues, but I don’t keep ATK running. I load it to kill the offending app, and have ATK set to kill itself at the same time as well.

    • StormbladeX69

      I just find using ATK for that is faster than wading thru to Manage Apps / letting the list load, and scrolling to the particular app, and then doing a Force Stop.
      I agree they shouldn’t be running all the time, autokilling things.

  • I don’t use the task killer to help battery life.  I use it to help my phone manage RAM better.  It helps speed things up.

  • Anonymous

    Yup. With my OG Droid, I found them necessary to juggle the feeble amount of available RAM, especially in the dark days shortly after the OG’s launch.  Memory management did improve considerably after the Froyo update (tell that to VZW employes, however!). 

    On my Droid X I had no need for them despite the laggy Blur but after upgrading to an X2 I occasionally had to employ one free up RAM to keep the phone from becoming incredibly sluggish (the latest 2.3.4 has helped this tremendously, however).  I think the X2 has a design flaw where it allocates too much RAM to the Tegra2 and you are always teetering on the edge of running out of RAM. 
    I have no such issues with my Acer Iconia running Honeycomb and don’t imagine needing to do it on any device with 1GB of RAM running Gingerbread OR on any future ICS device unless it’s to kill a misbehaving or poorly-coded app. 

  • Anonymous

    I stopped using a task killer a while back. Phone actually started to run better once I stopped constantly turning it on to kill apps.

  • alanmarchman

    I can see Verizon reps pushing task killers as a way to get customers back in to buy an overpriced extended life battery when they see no improvement with their phone. It’s ridiculous what they expect people to pay for accessories they can by for a fraction of the cost from Amazon.

  • PSU_DI

    I don’t believe in “task Killers” but there are apps out there that can save you battery life.  Juice Defender, specifically the Ultimate version makes android work smarter by a number of different tweaks and it truly does increase my battery life.  I used to get on average 8 hours max on my Thunderbolt with out needing a charge, I’ve doubled that to 16-20 hours with out changing my usage habits.  Things I like is the location awareness of my common wifi spots and the fact that it disables when I’m not in range, and also the fact that it limits the data usage of applications when the screen is off, plus like 30 other settings tweaks.  

  • on my Thinkpad Tablet, I use a “task killer” to kill all unnecessary apps when the screen shuts off. This most certainly increases battery life as before if i let it sitting in “standby” the battery would still drop about 35-50% over night. Now it has been 4 days of light use and no charging and my battery still is not dead. just an observation.

  • I have never thought that using a task killer would save my ancient Droid Eris’ battery.  What it does do, however is keep the phone’s RAM from becoming so bogged down that it’s almost unusable. When available memory drops down to about 22MB, the phone basically stops working.  The only way to fix it is to kill all the background apps.  I have it ignoring all the essential apps (messenger, gchat, gmail, etc) so it doesn’t hurt anything when executed.  Without the task killer on a phone this old, I would be restarting constantly.

    That being said, on my next phone (come on Galaxy Nexus!) I don’t imagine this will be a problem due to the obvious increase in RAM.

    • FortitudineVincimus

      AND better memory usage by ICS and advancements in multitasking and such.

      Even better when they start using more quad cores that tout as their big benefit even better memory and battery usage management.

      In an OG Droid I believe in them 100%. In a newer model like a Nexus, not likely needed.

      • Justin Kos

        ppl need to read these 2 comments, cant agree more

    • Anonymous

      it should be pointed out that the eris (if stock) is still running 2.1, which isn’t as optimized as 2.2 when it comes to task management. 

      • Mine is actually running 2.2 (tried 2.3 but it didn’t run well at all).   The Eris has a very small amount of RAM which, no matter what the OS version, will never give great performance when trying to do more than just the basics.

  • Anon

    But some apps that I use, like Google Music and PodTrapper, don’t have an exit command, so the only way to be sure they won’t start inadvertently playing music/podcasts at inopportune times is to kill them — or is there some other option?

  • Dominick DeVito

    Was this from a full charge prior? 9 minutes pass and by looking at the battery icon it looks like about 90% is left.


  • FortitudineVincimus

    I find it kind of funny that in fact, in 3 of 5 of those phones, a task killer did help and in only 1 case it hurt but the hurt was only by 2 minutes while those with a task killer gained way more more the mere 2 minutes.

    what a shitty claim then to say “task killers are evil” and “The verdict? They won’t” when in fact.. THEY DID!

    Nice spin job. Not a huge benefit, but not at all as bid as you make it seem.. if anything, it shows they DO help,

    • A gain of 15 minutes is not significant, and this was hardly a scientific, controlled study.  Who can say what actually caused that 15 or 10 minute difference.

      • FortitudineVincimus

        And a loss of 2 minutes, in 1 phone, is enough to say they do not work.

        If your going to put it out there at all and make a claim either way, then we must use the data you show and the data here simply shows a task killer DID help. sorry. I’ll take that additional minutes thank you,.

        • Anonymous

          the claim is in the %’s not the raw numbers:  4%, 4%, 0%, 0%.

          The effect is neglible, and in turn that since it generally costs money to use these (or even if it doesn’t, it wastes space on your phone), means they aren’t worth using.  Sure, he took a little liberty with the way he phrased it, but the gist of the message is the same.

          I personally disagree because they are extremely useful for killing applications that stay running without having to fumble with the native application manager.  I never use it to auto-kill apps, which is what they should point out in these posts.

          • The fact that the controls were likey loose in the study/test just allows for a certain amount of scientific error. The 4% gains or small loss probably fall well into that percentage of scientific error.

  • Anonymous

    Stop repeating “empty RAM is wasted RAM” like its some sort of slogan. It has nothing to do with why you want to use task killers. When I kill a task to free up RAM, it’s not because I like how pretty my RAM looks all empty. It’s because I want to use that freed up space for stuff that I actually use. If I’ve just finished using a memory hogging app that I only use once a month, I don’t want it to stay cached in RAM. Android kills background apps in least-recently-used order. So that app I just used might actually bump something that I use more often out of RAM. Now tell me why I shouldn’t kill that app that I almost never use so there will be more free memory to keep all the stuff that I actually use cached and ready to run?

    • There are only 2 excuses (that I can think of) I will accept for using a task killer.

      1) You are using Sense, or some other skin, on an old phone. Sense is garbage, and is especially horrible on old, slow phones.
      2) You have an app installed that is garbage and slows down your phone.

  • waveGuide3e8

    I have a question, then. I’m running ProjectElite Gingerbread on my OG Droid. I don’t use taskkiller apps, but I do regularly kill apps using the built in feature in the Settings menu. I don’t do it for battery life… I do it because some of my apps (like My Verizon, Google Maps, Gesture Search) will start on their own and slow the phone down. Typically if my phone runs slow, I’ll run CacheCleaner, and when that doesn’t work I’ll kill the apps manually. I typically see a noticable increase in performance.
    Am I just crazy and halucinating, , or am I pushing the phone to its limits, or what?

  • Kellexisabitch

    It did improved battery life. How stupid do you feel now? Dumbass.

    • Were you born this dumb? This is a Verizon blog, It DID NOT HELP any Verizon phone.

    • Anonymous

      Having a bad day? Turn that frown upside down!

  • Orion

    I agree with re: task killers, but I would add a caveat that programs like Watchdog, used properly, can be great tools.  I have found that when it alerts me or flags a program, it’s usually right.

  • Those that use task killers don’t understand what RAM truly is and what’s it’s for.  For the most part, empty RAM = wasted RAM.  It’s like having a giant warehouse and only using one corner of it.

  • Anonymous

    I actually find task killers quite useful when I have programs that are mis-behaving.  The ESPN Fantasy Football app always seems to get stuck on a page and refuses to load.  If I go in and kill it then it reloads and the program works again.  Yes I could go into Settings>Applications>ESPN FFL>Force Stop but that is a lot of work.  I think as long as you aren’t killing all apps randomly and just using it for when apps get stuck it is extremely helpful.  Don’t know as it improves battery life at all but it does serve a purpose (for me at least).  

    • Anonymous

      This is the only purpose to a task killer, and not one that most people use it for. The real solution, of course, is for ESPN to hire decent programmers for Android.

      • Anonymous

        I agree that it is probably not what most people use them for but I think that is based on mis-information. It just bugs me when these sites have anti-task killer posts that just rag on them altogether when there are in fact useful purposes these apps can serve.  Might be better to do a pros and cons post than to flat out call them worthless.  

        • Nick S

          I’m reading some comments that are calling task killers worthless but the article is only questioning their application toward increasing battery life, which they don’t.

    • I have CM7 on my phone and have set it to where if I hold down the back key, it force closes the currently open app. Works so much better for those cases since you don’t even have to open up another app. 

  • Anonymous

    Okay, my question… how the hell do you have 9+ hours on battery with only 22% display drain?? On my ‘rental’ RAZR my brightness is KILLING my batter (even with it set to 0%, though I usually leave it on Auto)

    EDIT: Does turning window animations off make a difference?

    • Playing music with screen off.

    • Angryunibrow

      I see 9m <— m not hours??

      • Anonymous

        Yup, mis-read!

  • Skinja99

    Also. Has any one invented a way yet to only have LTE on when the screen is on?
    That way back ground stuff like email would be syncing with 3g.

    • escobar

      Yes there is a developer for the Thunderbolt that has 4g auto on/off

      • Damn, you beat me to it.  I saw the comment and was going to say that I’ve got this on my phone 😛

    • Anonymous

      Sounds like a good idea but then you would have both you antennas running killing the battery even faster, plus if its on 4g then it does it faster using less time and hopefully saving a bit of battery along the way. I want to know if there is a way to only have 4g on so it is not bothering at all with the 3g antenna.

  • Mc123

    What about WatchDog?

  • I don’t put it on my phone for battery enhancement, I put it on my phone for speed enhancement.  Hell I’ll take another 4% battery life with that speed.

    • Anonymous

      It actually kills your speed for most day to day use. Sure, it can help to peg a benchmark; but it sucks when you have to basically launch every frequently used application every time you want to use it. Browser, Talk, Voice, ADW/LP, etc. are all very nice to have in RAM almost all the time.

  • Skinja99

    What about for processing and memory power?
    Will video or games run more smoothly if background tasks are killed?


  • Dominick DeVito

    Kellex – nice try. But we didn’t forget about the G-Nex.  :p

    • OG Droid

      Yeah must be a slow news day

      • jar

        Every other tech site seems to already have the G-NEX… for the first time ever droid life seems to be letting me down

        • OG Droid

          I know I want one sooo bad. At least we know at worst(hopefully) it will be here at the end of the month.

        • Anonymous

          They have always been behind on phone reviews though. 

    • Right, your simple one track mind can’t handle any other information. Overload, Overload. 

      • Dominick DeVito

        Stay classy Rocko.

        And be sure to keep a dictionary handy at all times.

        • You are hurting yourself replying to me. Stop wasting precious brain cells, you need to conserve them for Nexus news.

        • Bobby_Bouche

          Simpletons need repetitive stories on single topics or they get the brain pain coach. 

          • Bobby would love the Nexus. Has Vicky Valencourts phone number on speed dial out of the box.

          • WAldenIV

            Funny thing is the correct spelling is “Boucher”.

  • Guest

    They seem to work. Ignoring all the other crap and the back and forth, those results show they DO improve battery life. I am sure as dull not going to be installing one soon on my cyanogen, but to toot the horn of…HAHAHA TOLD YOU SO is Judy plain stupid. It would be nice to see a larger sample size but if anything of says that yes, it CAN help

  • Anonymous

    The debate is closed people.  Now the government must get involved in order to stop these task homicides.  It’s out of control.

  • Dominick DeVito

    It’s like opening Task manager in Windows and ending every process in there. Can it help? Maybe. Will it help? probably not a good idea – will do more harm than good. This isn’t much different.

    Writing task killers was a way for devs to make a quick buck, and for that, I can’t blame them.

  • Richard Yoo

    On an unrelated note, ICS has been successfully ported to Galasy S2. 

    Talk about Galaxy Nexus being the first phone to run ICS tsk tsk.

  • I want to see what effect a task killer has on stock. Both stock Gingerbread on the Nexus S and stock ICS on the Galaxy Nexus.

    • Spectreoflight

      Remember, ICS has a built in “task killer”. It the new multi-tasking it has where you can swipe away the app to close it. So this should help your test. I still think any other apps are pointless for this task though. 

  • viewthis74

    i don’t use task killers anymore but what about programs like Lookout?

    • That will certainly kill your battery life it runs in the background constantly syncing 

      • viewthis74


      • WAldenIV

        No it doesn’t.  If you set it to scan apps that you install and do a weekly system check it takes almost no battery at all.

  • Anonymous


  • Anonymous

    I don’t use a task killer to try improve battery life, that was never my intention for using a task killer, I use it because if my OG Droid has more than a couple things running it will slow to a crawl or force quit applications. And if someone has an alternative method for preventing this please share, until then ill use advanced task killer.

    • Don’t install garbage apps that run in the background all the time.  I have an Eris (much less powerful the OG Droid) and I’ve never used a task killer, and my phone runs smooth for it’s age.

      • Anonymous

        I have had a similar experience with my Eris.  I agree.

      • Anonymous

        I had similar experience with my OG Droid; especially on GB. Bottom line: if an app is causing the problem, kill the app (uninstall or turn synch off); don’t kill Android’s garbage collection or your quick access to frequently used apps (task killer).

        • Anonymous

          Agreed. If an app is killing your battery life, uninstall it and give it a bad rating for God’s sake…

  • This is news?  I wasn’t aware anyone was still using these garbage scam task killer apps.

  • But…but…the results show an improvement on some phones so it must be true that it helps battery!

    • All that work for 5 min more, I totally want to use one now /s

  • John

    I wish in store reps would stop suggesting people to run a task killer. I’ve seen that way too many times on forums

    • Anonymous

      The over the phone rep told my wife to do the same thing. I removed it from her phone immediately…

  • Dan

    The Verizon in-store rep ensured me if I put on a task killer on my phone, it would run a lot better. How is this so called PC World have any credibility. I assume Verizon would only hire the brightest and most sought-after employees. 😛

    • Anonymous

      haha i just put in an application. two of my friends work there and they call me for their phone help… i’m pretty sure they have a hard time figuring out how to open the app drawer. maybe that’s why one has an i*hone

    • Anonymous

      I work for a VZW store and they actually encourage task killers in their trainings…I got into a huge argument with the course trainer about it its pretty pathetic

      • Anonymous

        Went about as well as a fart in a phone booth I’m sure =)

      • It’s funny because tech support does not recommend them at all.

      • GoW

        I also work at a VZW store, but luckily it’s a Go, so we aren’t forced to go through the same trainings.  I instantly ask to uninstall every single task manager that a customer brings through my door.  Luckily I’m the SM, so it makes my credibility go through the roof, and most people listen to me and do it.

    • Kmac940

      well were not all created equal lol. I work for Verizon via Cellular Sales and take it off every phone I see!!! I have having to fix the issues these things cause! I also dislike the idiot/ignorant reps putting these on without proper knowledge of it’s effects!

      • Rogercollier4g

        Me 2… Thumbs up CSOKI

    • guest.

      where have you been for the last few years? pcworld has more credibility than a verizon rep..

    • Piemasta93

      your an idiot…
      the dev community knows much more about phones then 90% of the people that work at verizon.

      • Dan

        Sarcasm, hence the emoticon. No worries, I am well-versed when it comes to the Android operating system 🙂

    • edsaway


  • Anonymous

    i pity the fool who be using a task killer!

  • Richard Yoo

    I thought the whole point of task killer was to prevent RAM from bogging down.

    • Anonymous

      No. Android clears RAM when needed. that’s the point. They actually make your phone run slower because android keeps thing that you may open in memory, allowing it to be opened and run faster. then when it needs more memory, it kills off an old task. which is why task killers are unneeded. the OS does it for you.

    • RAM shouldn’t bog down. Android does a good job of managing memory on its own. No need for a task killer.

      • RAM is a storage so When you want to use more it just gives you more, there is no bog down. Using RAM on andorid prevents CPU cycles which then save battery (It requires less energy to pass electricity through RAM and keep it active, which it always is active)

      • Tell that to my Eris…

    • That doesn’t even make sense.  How does RAM “bog down”?  If anything, you want you RAM full with all the apps you use most frequently, that way you can switch between them and multitask quickly.  Empty RAM = wasted RAM.