What is kernel_task and why is it taking up so much memory?

Discussion in 'Mac Basics and Help' started by troye, Jun 27, 2012.

  1. macrumors newbie

    Joined:
    Apr 10, 2012
    Location:
    Lubbock, TX
    #1
    I have 4GB of RAM on my iMac and this kernel_task is taking up between 335MB-450MB.

    This is making it hard for me to run both Motion 5 and Final Cut at the same time.

    What is kernel_task and is there a way to make it take up less RAM at any given time? Thanks.
     
  2. macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #2
    Kernel task is your operating system.
    1. Launch Activity Monitor
    2. Change "My Processes" at the top to "All Processes"
    3. Click on the CPU column heading once or twice, so the arrow points downward (highest values on top).
    4. Click on the System Memory tab at the bottom.
    5. Take a screen shot of the whole Activity Monitor window, then scroll down to see the rest of the list, take another screen shot
    6. Post your screenshots.
     
  3. thread starter macrumors newbie

    Joined:
    Apr 10, 2012
    Location:
    Lubbock, TX
    #3
    Here is the screen shot
     

    Attached Files:

  4. macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #4
    Read step #2 again. It's in bold text.
     
  5. thread starter macrumors newbie

    Joined:
    Apr 10, 2012
    Location:
    Lubbock, TX
    #5
    sorry about that.
     

    Attached Files:

  6. macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #6
    Everything looks normal to me. It doesn't look like anything should be contributing to performance problems.
     
  7. macrumors regular

    Joined:
    Aug 17, 2011
    #7
    Not really, because you still have nearly a Gig unused. Neither program is paging VM at any particular heavy rate, so a lack of RAM is not your bottleneck, and more RAM will likely not help.

    The best thing is to run them separately; if that is impractical, you need a bigger boat.
     
  8. macrumors member

    aismaiil

    Joined:
    Aug 1, 2012
    #8
    Hi there. This is my screen shot. My kernal_task goes up to 700MB sometimes when I have no applications open whatsoever other than finder, activity monitor and safari. I just want to know whether it's normal or not, because I know RAM has nthing to do my MBP's performance as I upgraded it to 8GB and I have over 4GB of free RAM, but it gets really slow sometimes with the beach ball being a pain in the a**, I don't know whether I should just switch my HD to an SSD! Thanks :)
     

    Attached Files:

  9. macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #9
    The Mac OS X kernel_task will use varying amounts of memory and CPU, depending on what it's doing. You have plenty of memory available and no page outs, so any performance issues you may have are not memory-based. If you're getting beachballs on Safari, it could be Flash-related. For Flash-related issues:
    • Find your Flash version and make sure it's the latest version available. Never install or update Flash from a pop-up on a website. Always go to Adobe's site to get Flash or updates.
    • Install ClickToFlash (Safari), Flashblock (Firefox) or FlashBlock (Chrome) to control which Flash content plays on websites.
    • Try using the YouTube HTML5 Video Player to watch YouTube videos, when available. (May impact fullscreen viewing. See link for details.) Some have reported better performance with HTML5, while some have reported worse. Try it and find out what works best for you.
     
  10. macrumors regular

    TweakOnline

    Joined:
    Dec 17, 2012
    Location:
    Europe
    #10
    Guys, is this normal?
    On my 15'' MacBook Pro Retina Kernel Task uses more than 1GB of ram, why!?
     
  11. macrumors G5

    gnasher729

    Joined:
    Nov 25, 2005
    #11
    Because you have plenty of RAM, and if it isn't used, it is useless and you might as well not have it.
     
  12. macrumors regular

    TweakOnline

    Joined:
    Dec 17, 2012
    Location:
    Europe
    #12
    8GB of ram isn't much and if I'm using Adobe Photoshop or Aperture it still uses up to 1GB of ram.

    Next time I'll buy a Mac it will be definitely have 16GB of ram... :/
     
  13. macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #13
    OS X will use whatever RAM is available. That's what RAM is there for. It doesn't mean you're maxing out your RAM if it's all being used. The only thing you need to watch for is page outs under normal workload.

    To determine if you can benefit from more RAM, launch Activity Monitor and click the System Memory tab at the bottom to check your page outs. Page outs are cumulative since your last restart, so the best way to check is to restart your computer and track page outs under your normal workload (the apps, browser pages and documents you normally would have open). If your page outs are significant (say 1GB or more) under normal use, you may benefit from more RAM. If your page outs are zero or very low during normal use, you probably won't see any performance improvement from adding RAM.

    Using Activity Monitor to read System Memory and determine how much RAM is being used
     
  14. macrumors newbie

    Joined:
    Jan 20, 2013
    #14
    kernel_task is above 200%

    Hi,

    I have 13in MacBook Pro. It is 1 year old.
    4GB RAM
    500GB Hard Disk
    2.4GHz
    10.8.2 OSX

    I think high %CPU use of kernel task is because of flash

    I have attached two screenshots.

    Thanks
     

    Attached Files:

  15. LPZ
    macrumors 65816

    Joined:
    Jul 11, 2006
    #15
    It seems very unlikely to me that it is caused by Firefox/Shockwave Flash. Did you quit Firefox and then check if kernel_task used less CPU?

    I'd check to see if you have an third-party kernel extensions, and try removing those. Or start with a Safe Boot and see if the problem occurs then.
     
  16. macrumors newbie

    Joined:
    Jan 20, 2013
    #16
    How can I find third party kernel extensions and how can I safe boot? I noticed when play chess from chesscube.com which uses flash, kernel task is going up from 5% to 220% and system got slow. Also my Mac is getting very hot in 30 mins. Is this normal?

    I used to play chess but I have never experienced this problem until last 3 days.

    Do you think this is because my mac is getting very hot? I was not using flash player but the kernel task went above 300%

    I will try to safe boot and check. I have attached another screenshot
     

    Attached Files:

  17. macrumors newbie

    Joined:
    Jan 20, 2013
    #17
    LPZ,

    I ran mac in safe mode...kernel task is below 10% even though I ran flash but the system got slow like in normal mode.

    Attached is a copy of screenshot

    Thanks
     

    Attached Files:

  18. LPZ
    macrumors 65816

    Joined:
    Jul 11, 2006
    #18
    There are no page outs, so you have sufficient RAM. In the screenshot, you do have two browsers open, and it appears that Spotlight is working at indexing your filesystem. That could explain the slowness.

    To see if any third-party kernel extensions are involved, reboot without using Safe Boot and then open Terminal (in Utilities). Copy and paste the following into Terminal and press return:

    Code:
    kextstat | grep -v com.apple
    This should produce a list of any non-Apple kernel extensions that are loaded (if any). Please post the output.
     
  19. macrumors newbie

    Joined:
    Jan 20, 2013
    #19


    There might be malfunction of a exhaust fan. I installed iStat Pro and it says exhaust fan is 0rpm. My Mac is over-heating, especially on the left side of the keyboard. I am not hearing fan sound from last 2 days. Before that there was weird sound coming from my fan (for couple of mins and then goes off), it is like a cracking sound. I thought there might be dust particles in my fan. Now I do not hear fan sound at all. Do you think this might be the reason for kernel_task having high % CPU?

    I am unable to run AHT. I guess I need to connect my Mac to ethernet and then try AHT. Do I need to run SMC? Clear the dust particles in the exhaust fan?

    I will check for kernel task third party extensions and let you know.

    Thanks



    Thanks
     
  20. macrumors newbie

    Joined:
    Jan 20, 2013
    #20
    Below is the output I got

    Last login: Sun Feb 10 09:56:23 on console
    Phalguns-MacBook-Pro:~ Phalgun$
    Phalguns-MacBook-Pro:~ Phalgun$ kextstat | grep -v com.apple
    Index Refs Address Size Wired Name (Version) <Linked Against>
    Phalguns-MacBook-Pro:~ Phalgun$ kexstat
    -bash: kexstat: command not found
    Phalguns-MacBook-Pro:~ Phalgun$ kextstat | grep -v com.apple
    Index Refs Address Size Wired Name (Version) <Linked Against>

    In one of the forum I posted, they suggested me to replace my logic board.
    I guess my exhaust fan is not working, my Mac is getting heated up. Do you think I need to replace logic board? I thought cleaning my exhaust fan would work
     
  21. macrumors 603

    thekev

    Joined:
    Aug 5, 2010
    #21
    It's because the OS has become bloated in recent versions. It may sound silly, but that is basically the problem.

    Flash sucks on macs, but it could just be doing stuff in the background. They do get hot. I want you to go look up the definition of kernel so you better understand it. The kernel essentially allows the OS to communicate with underlying hardware. You can't do much regarding the amount of resources it consumes. If you think you have a problem, take to Apple or run hardware tests. Do not make assumptions without data.

    How hot? Macs do get hot, and I mean really hot. Replacing the logic board won't change that, and I'm not sure you realize how expensive that is. The logic board is the most expensive component in the thing due to how much stuff is permanently attached.
     
  22. macrumors newbie

    Joined:
    Jan 20, 2013
    #22
    The left side of the laptop is hot compared to the right. iStat Pro says the CPU temperature is around 54 to 80 deg C.

    Logic board is really expensive. I guess it costs more than $1000.

    Does malfunctioning of exhaust fan requires replacing logic board? There might be dust particles stuck in the fan. Should cleaning the fan would work?

    Thanks

    ----------


    I am unable to run AHT on my Mac. There is no apple store at my place. :)
     
  23. macrumors 603

    thekev

    Joined:
    Aug 5, 2010
    #23
    They can get this hot even if the fan is fine. Some people have lowered their internal temps by replacing the thermal paste on the cpu and gpu. Either way these temperatures aren't really uncommon among Macs.

    They used to bundle it with the OS reinstall disks. I'm not sure now. I'd have to look it up.
     
  24. LPZ
    macrumors 65816

    Joined:
    Jul 11, 2006
    #24
    OK, no third-party kernel extensions.

    About the CPU temps--they really don't seem that high for a multi-core machine that is making heavy use of the CPU. Of course, cleaning an exhaust fan can't hurt, but I wouldn't be thinking of replacing a logic board (or anything else) right now. There are apps available that can be used to modify fan speeds, to provide extra cooling. One is called smcFanControl.

    If you have the original OS install disk for your machine, load that disk and then restart holding the D key. This should get you the Apple Hardware Test.

    But the real issue remains---is kernel_task still using 200% CPU after a normal boot? And if so, why?
     
  25. macrumors newbie

    Joined:
    Jan 20, 2013
    #25
    I have both smcFanControl and iStat Pro. The fan speed is 0 rpm in both the apps. I have changed the fan speed in smcFanControl but nothing happened. I guess the exhaust fan is not working.

    I don't have OS install disk. I tried to boot holding D key but it didn't work. I even tried connecting ethernet and booting but it didn't work too. Are there any other techniques for doing AHT?

    I noticed the kernel_task is above 200% when I am watching movies or using flash and when the Mac is getting hot.

    The CPU Temperature was 80-90C (not F)
     

Share This Page