iOS Multitasking Video Clarifies Why ‘Killing’ Apps Isn’t Necessary

Earlier we further learned about iOS multitasking as detailed in a post by Fraser Speirs. As much as the debate continues about whether or not we need to ‘kill’ apps in the multitasking tray, Speirs has now posted a detailed video of how iOS multitasking works as we get to see memory and CPU management in real time on his iPad.

There are five sections to this video demonstrating:

  • An app going from active to background to suspended
  • Instacast HD requesting extra background time to finish a podcast download
  • TomTom running indefinitely in the background
  • Batman Arkham City Lockdown and Real Racing 2 HD competing for big chunks of device memory
  • Batman Arkham City Lockdown forcing several smaller apps out of memory

His conclusion remains that force closing apps is fine for troubleshooting but should not be required as a regular routine.

Check out his 17 minute video below and tell me what you think:

Founder and Editor-in-Chief of iPhoneinCanada.ca. Follow me on Twitter, and @iPhoneinCanada, and on Google+.

  • Daniel

    I close background apps to preserve battery power

  • Sevael

    This recent flurry of multitasking articles keeps talking about freeing memory.  I’m pretty sure that most people don’t care about that – we do it to conserve battery life, which is clearly proven to be an issue.

    They can connect iOS devices to computers and run all the tests they want, but what it all comes down to is that we can all prove the battery issue right on our own iOS device(s).  If I leave certain apps like the official Twitter app running in the background overnight, I lose almost 20% more battery in standby than I do killing the app before going to bed.

    No video is ever going to make that cold hard fact go away.

  • Chris

    Personally, I kill the apps that run in the background for 2 reasons. 
    1. To free up RAM as since 5.0.1 was installed on my 3GS, it ends up with 2Mb of free RAM and slows down everything, including the keypad from opening up. 
    2. To save battery live.

  • Daniel Lee

    Completely useless video, anyone who kills apps will do so to conserve battery life, not to recover Memory or CPU. My co-workers, who have iphones, do it for the same reason. Do not bother watching the video as it has nothing to do with proving that not killing tasks will save battery life. It is only concerned about Memory/CPU.

  • Anon

    You kill apps to preserve battery life.  It’s just common sense.  TomTom GPS app and many others can quickly drain the battery.  The guy in that video is an idiot.

  • Anonymous

    Much like those who have already posted I kill my apps to conserve battery life and it’s a noticeable difference.

  • Cshudson

    So why does garage band on my ipad1 crab unless all other apps ate closed. Hmmm …

  • Cshudson

    Crash, not crab 🙂

  • Cshudson

    Are , not ate. Jeesh, I must be hungry…

  • Kyle

    I’m not convinced by most of the arguments against multitasking in the comments so far. Yes, apps which are ‘active’ when running in the background such as those actively streaming audio, or actively using the GPS use additional processor time. This increased processor time decreases overall battery life.
    The article is attempting to show that apps that are suspended when running in the background (which almost all are) don’t use the processor very much at all and so should have a minimal effect on battery life. Furthermore, there is no additional power cost to using memory. The DRAM itself will use the same amount of power regardless of the amount of memory being used. Other than CPU and memory use, I can’t think of anything else about multitasking that might affect battery life.

    I can’t speak to the specific instances of increased battery consumption that some users claim to experience when multitasking. Personally I think it may be due to issues involving cell signal strength. If your device is having trouble staying connected to a cell phone tower or has a very poor signal, it will definitely use up more power than normal.

  • Anonymous

    Open up ten apps and watch your battery disappear because it will. My battery always lasts longer when I kill the apps after use.

    If it didn’t I wouldn’t bother but when I’ve forgotten to kill them off the battery reduces much faster.

  • Anonymous

    I personally never noticed the battery life issue, but I never paid much attention to it either. On my Galaxy S2 I can see all the suspended apps, their CPU usage (typically 0.00% but the odd jump to 1-2%) and RAM usage. I would assume that android and iOS function fairly similar on this, so I can definitely say that suspended apps do use a little bit of power running in the background, however it is probably less than them opening and closing often to check for data etc.

    What I did notice on my 3GS is that with multitasking enabled I would run out of RAM very quickly and my phone would become nearly unusable. Some apps were terrible for this (TomTom) while others didn’t seem to contribute. I constantly was clearing my memory with SBSsettings to free up RAM, perhaps this isn’t an issue with the 4 or 4S.

    While there may be no difference for some apps, I’m sure some definitely cause a battery drain, just depending on what it is. For example, a messenger app is probably more efficient being in a suspended state for push data than opening and closing, but a game or something should be closed.

    Honestly if the phone is fast enough, you don’t need multitasking much. Likewise if the battery is good enough, it doesn’t matter either.

  • Anonymous

    I regularly kill all background apps to free memory and save battery life. I have SBSettings installed on my iPhone and set it to show RAM on the status bar. A fresh start will give me about 320 MB and the number goes down everytime I open a new app, especially 3D game that it quickly drop the RAM to less than 50MB. ie. now, I have 15 apps running on the background and this one on the foreground. The available memory is only 26MB now. It normally slows down those 3D games while smaller apps run ok. I beleive killing background apps is very important to free memory and save battery life. It will also give you faster response time when you open a new app.

  • JSH

    Leave the Garmin navigation app open and in the background after using it and see how far you get.

  • Woody

    Ive tested this on my 3GS and iPhone4 both on 4.2.1. When  I leave a game(My Horse) suspended in the task bar when I go to bed my battery will drain from 100% to 95% overnight and my Ram will drop from 130mb to 52mb on my 3GS. If I kill the game my battery will stay at 100% overnight. Same goes with my iPhone4 except the Ram goes from 350mb to 220mb when the game is left in the task bar. I have my phone set to kill all apps except the ones I want to run in the background like the ipod. I dont know why they are trying to make a big deal about Apple’s multi tasking all of a sudden. Its been crap since it was first implemented. Backgrounder is still the best for doing this.