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kernel_task consumes a lot of RAM in early 2011 MBP, sometimes Finder too

172286 Views 215 Replies Latest reply: Mar 17, 2014 9:46 AM by Attila RSS
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DChabot Calculating status...
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Mar 16, 2011 12:04 AM

My old MBP3,1 (late 2007, 2.4 GHz Core 2 Duo) worked quite well with 4 GB of RAM, even after weeks without restarting. In fact, I used all available RAM only on some larger analyses using R, which loads the entire dataset in memory. To be able to run these few analyses faster on my new machine (early 2011 MBP), I bought the 8 GB RAM option.

In Activity Monitor, I noticed something strange. Whereas my old MBP shows kernel_taks as using between 100 and 200 MB of RAM, the new MBP uses about 550 MB just after the machine started up and often shows over 600 after a few hours or days of use. A one year old iMac, again Core 2 Duo with 4 GB of RAM, gives a kernel_task memory usage below 200 MB after weeks of use.

I've not been able to find what kernel_task does. Is this amount (around 600 MB, but it has gone up to 800) normal? Is it managiing the additional number of cores that requires this behind the scenes amount of RAM?

Anyway, I now quite often have more than 4 GB of RAM in use even when I have only a few applications running (not even including R!), which surprises me.

Also today, after moving a lot of files back and forth between an external drive and the new MBP, after emptying the garbage can that contained a hefty number of files and doing a first Time Machine backup, the Finder ended up using 2,4 GB of RAM according to Activity Monitor. I have never seen anything like this (although I admit not having Activity Monitor on all the time). Even after the backup was finished and the external drive disconnected (in fact the machine was left idling for a few hours) cpu usage was down to nearly zero, the Finder kept its 2.4 GB of RAM. I restarted and the new RAM usage for the Finder was 26 MB. I have a screen shot showing the 2.4 GB, but I could not find a way to attach it to this message. I can send it by email on request. I don't think this Finder behavior was normal.

Somewhat worried,

MacBook Pro 2.2 GHz i7, 8 GB RAM, Mac OS X (10.6.6)
  • homenucleonic Calculating status...
    Same here. MBPro 2011, 2,2 Ghz 8Go ram
    Kernel_tarsk consuming from 450 to 800 Mo..
    I use lot of ram in audio applications (logic9, spectrasonics, eastwest, toontrack..), 800 Go of soundbanks located on external DD with sonnet tempo sata card.
    I've built the exact software copy of my Mac pro (quadcore intel 2010) on witch Kernel task runs under 200 mo..
    Everything else is fine, CPU usage is normal, but it's still ennoying..
    Didnt found any solution on the net..

    THX for telling me if you find something
    JM (france)
    MBP 2011 Qd 2,2ghz 8Go, Mac OS X (10.6.7)
  • Ankhanu Calculating status...
    I've got the same thing going on with my new 15" MBP (4Gb RAM). kernel_task is currently eating 607.9Mb of my memory. I don't recall it ever being an issue with my early 2007 13" MacBook w/ 2Gb RAM.
    15" MBP (2011, quad i7 2.2GHz, 4Gb RAM), Mac OS X (10.6.7), iPhone 4, iOS 4.3.1
  • Gerard Klein Calculating status...
    Same here. Got a brand new 2011 MBP with 8GB ram. Strait after booting, kernel_task is at 670 MB. Could it be that 64 bits has anything to do with it? After (if I'm not mistaken) all until now, all machines (except the new Pro's) run in 32 bits mode by default, these MBP run 64.
    If I stress the machine a bit, kernel_task is close to 900 MB.
    MBP 15 2.0 i7, Mac OS X (10.6.7)
  • LSUAMDG Calculating status...

    So there is still no information or update concerning this issue? What's the point of 4 GB of ram if you can only use half of it?

  • AnD3rS Calculating status...

    I've got the same issue on my 2011 MBP (15", 2,0Ghz 4GB Ram).


    kernel_task is using about 500MB Ram right after booting, also there is a lot of Ram reserved.

    In combination with starting a virtual machine, it completely hangs my machine because of the whole swapping...

  • wyager Level 1 Level 1 (0 points)

    This seems to be a problem with the new macbooks. I have the lower-end 15" 2011 MBP with 4 gigs of RAM, and my kernel_task consumes around 600 megs all the time. Apple, can you help us out here?


    Additionally, my wired memory is always huge (sometimes over 1 gig) and the amounts of memory usage reported in activity monitor per application and total do not add up. I'm not sure if these are related. I'm not even sure where the RAM used by kernel_task goes, into wired or active memory.


    Edit:DChabot, I read your second message, your RAM problem is EXACTLY like mine. All of the processes add up to 1.5 gigs, but the reported is 2.36 gigs (1.06 wired, 1.30 active). This happens consistently.

  • LSUAMDG Level 1 Level 1 (0 points)

    So I found this post in the related articles section.




    It's pretty old, but it looks like the problem reared its head back in 10.5. I think it might be because OS X knows it has the memory to allocate for kernel_task, so it really just does it without much direction from the user. Im reading ~350MB with an uptime of about an hour right now, but earlier I ran Parallels and it was embarrassingly slow, with the memory split 50/50. It does get bad though, when it spikes to about 550, 600MB. I'm going to the Apple store tomorrow to see if the "Geniuses" can give me a good explanation.

  • wyager Level 1 Level 1 (0 points)

    Thanks for the info. Maybe consider pointing the Geniuses to this thread, so they can see that this isn't just your problem and maybe they can submit a report back to apple or something.


    Let us know if you find a solution, this is a real PITA!

  • numonium Calculating status...

    I recently finally upgraded to the new, beautiful Sandy Bridge (Early 2011) MBP from the original MBP 1,1 in 2006. The 1,1 had 2GB of RAM, and its kernel_task was using about 250MB RAM at any given time.


    Booting up my new MBP, with nothing open, no menu items, etc. kernel_task uses 650MB+ before I even do anything. My new MBP has 8GB of RAM, so it's not a "huge" issue, but I thought I would never have to worry about memory usage with a laptop as powerful as this.


    Both laptops were running 10.6.7 - what gives?? I shouldn't have to check Activity Monitor this much on such a new computer. I can see that my new MBP uses twice the RAM as my old one did, doing the same tasks.


    Perhaps a memory leak is to blame? I'm going to test under Lion and see if maybe the 10.6.7 kernel is the culprit.

  • numonium Level 1 Level 1 (0 points)

    Attached you'll find two screenshots: the first is Activity Monitor taken on an i7 MBP 2011 with 8GB RAM in 10.6.7. Nothing else is open except for Finder; you'll notice that kernel_task is using a lot of RAM:

    snow leopard - activity monitor.png

    Unfortunately, in the second screenshot, you'll notice that Lion DP3 exacerbates the issue, increasing kernel_task RAM even more:

    lion-activity monitor.png

    To Apple/Steve/Geniuses: What gives??


    I hope you don't give any "Microsoft/Windows-esque" arguments in reply, such as:

    1. If you have more RAM, Windows OS X will use it
    2. This is actually a performance increase.


    I would totally believe the caching argument, except that both screens were taken immediately after a cold boot, so nothing would be in the OS cache. I'll cross my fingers and hope that 10.6.8 and its respective Lion update will fix this problem. This is definitely not the performance I was hoping for after blowing my life savings on a (still) amazing new computer.

    MacBook Pro, 10.6.7, Lion DP3, 8GB RAM, i7 Quad
  • wyager Level 1 Level 1 (0 points)

    "This is definitely not the performance I was hoping for after blowing my life savings on a (still) amazing new computer."


    I hear that... Come on, Apple.

  • eww Level 9 Level 9 (52,975 points)

    You aren't talking to Apple in these forums, so don't bother telling Apple what to do. We're all just other Mac users here.

  • wyager Level 1 Level 1 (0 points)

    No kidding, I'm not literally trying to talk to Apple... lol.

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