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Kernel Task - 670% of CPU HELP! :)

N

NoClueWhat2Do

macrumors newbie
Original poster
Jul 17, 2014
5
1
Hi there,

My macbook pro has recently started to run achingly slow. After researching online looked at my Activity Monitor and find this line:

kernel_task - 670% of CPU - 98 Threads - 600mb+ Real Memory (Intel 64bit)

This is definitely the thing that is slowing down my computer as sometimes it will go and the computer will instantly be fine again.

I cannot seem to find out what the dam kernel task is, and how to fix this.

Computer specs:
Model Name: MacBook Pro
Model Identifier: MacBookPro8,3
Processor Name: Intel Core i7
Processor Speed: 2.3 GHz
Number of Processors: 1
Total Number of Cores: 4
L2 Cache (per Core): 256 KB
L3 Cache: 8 MB
Memory: 8 GB

Does anybody have a clue what to do please? I am total rubbish at computers and so if you do know could you explain it as if to a child?

:) Thanks so much for any help in advance
 
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Please take a screen shot of the activity monitor. Make sure the CPU button is selected and you're sorting by CPU (and make sure its set for all processes).

The Activity Monitor is found in the Applications->Utilities Folder.

Activity%20Monitor%20(All%20Processes).png
 
Hi maflynn,

Firstly thanks very much for having a look at this. Sorry tried to do this earlier but it was taking too long as my computer is too slow!!

Ok so this is the current state of my activity monitor (attached screenshot).

I have actually noticed something that may be of help:
- This problem seems to occur when I plug my macbook pro into my thunderbolt display...
- Sometimes my thunderbolt display works fine, but for example, if i am watching a Youtube video, and decide to watch it on the bigger screen, and I plug in the display, the kernel task goes nuts and the computer seems to come to a stand still.

Sorry for late reply but this has take me like 20 minutes as everything takes so much time on my computer!!!

Any help would be awesome, thanks so much

ps I have got CleanMyMac2 etc and have used it to clean up loads of stuff, but made no difference. Thanks :)
 

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I see Sophos and the Sophos related Intercheck chewing up a lot of CPU cycles there. I would uninstall all the Sophos stuff and see if that helps.

You also have something going on in one of your Chrome tabs chewing up 100% of one CPU core. Any idea what that is?
 
GhettoMrBob said:
I'm guessing that's YouTube running since he put that in his last post.
Click to expand...

Yeah maybe, but I am running a 1080p YT video in a Chrome tab now on my MBA attached to a TB display and it peaks at around 38% for that process, so something odd is going on with the OP and Chrome.
 
Hi everyone,

Thanks so much for the help and posts.

I have got rid of Sophos, and it has helped insomuch as that the kernel_task is now closer to 500%.

However the machine is still practically unusable!

Please see the 2 new attachments, that is the top and bottom of the activity monitor, there seems to be a hell of a lot of rows there, not sure if that is normal.

And you're right the google chrome helper thing does take up loads, and it's like that when I'm watching youtube vids / streaming movies.

Thanks very much :)
 

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Chrome/chrome helper is also using a total of about 200%...I would uninstall that.

If you can, I would backup your mac and just do a fresh install of Mac OS
 
NoClueWhat2Do said:
Hi everyone,

Thanks so much for the help and posts.

I have got rid of Sophos, and it has helped insomuch as that the kernel_task is now closer to 500%.

However the machine is still practically unusable!

Please see the 2 new attachments, that is the top and bottom of the activity monitor, there seems to be a hell of a lot of rows there, not sure if that is normal.

And you're right the google chrome helper thing does take up loads, and it's like that when I'm watching youtube vids / streaming movies.

Thanks very much :)
Click to expand...

You still have some Sophos stuff running there, so you did not get it all. Also MDworker is running, so that means Spotlight is still indexing... so wait for that to finish.

I am puzzled by the Chrome CPU usage even though it is a YT video.

Try a safe mode boot and see it it does it then. Safe mode stops any startup or login items from running.
 
I'd also look to getting rid of/killing Chrome and its processes. That's been known to cause performance and stability problems on Macs, specifically rMBPs
 
Xgm541 said:
Source?
Click to expand...

That's correct :D
Chrome is often a source of high CPU use.
It's just not your best browser choice, particularly if you want good battery life on a MBPro.
My theory (for what it is worth…) is that if Chrome ever goes to 64-bit, then processor usage may go down (I would hope the processor and RAM will be used more efficiently then - but I could be way wrong on that)
 
Thanks all,

Yep the problem still remains even if i use another browser, but will see what I can do about the chrome issue too.

Perhaps this is the issue?
http://www.rdoxenham.com/?p=259

Seems this guy says its about temperature control? This kind of makes sense as the problems have just occurred recently when we've been having a heat wave here in the UK....but I don't really understand a clue of what he is saying!!!

Should I do a re-boot of OS? Don't have a clue how to do that but can try.
Thank you :)

ps I did a safe mode boot thing and still the problem occurs, thanks
 
Last edited:
NoClueWhat2Do said:
ps I did a safe mode boot thing and still the problem occurs, thanks
Click to expand...

If you did a safe mode boot and kernel task is still pegging out the CPU even without Chrome running, I think it is time to just reinstall the OS over top of itself and see if that helps.

Make sure you have a backup first just to be safe, but this won't erase your data.

Just command-r boot to recovery and click reinstall OS X.
 
Hi,

Thanks for all the suggestions and replies.

Nothing has worked though. The kernel task just pops up from anywhere between 2-10 minutes, and makes the computer unusable.

Sometimes happens when i plug it in to power source, or if I put the thunderbolt display in, or if i go to clamshell mode. Seems to be directly related to those things somehow.

Anyway, guess il take it to the mac store or something, thx
 
NoClueWhat2Do said:
I have actually noticed something that may be of help:
- This problem seems to occur when I plug my macbook pro into my thunderbolt display...
- Sometimes my thunderbolt display works fine, but for example, if i am watching a Youtube video, and decide to watch it on the bigger screen, and I plug in the display, the kernel task goes nuts and the computer seems to come to a stand still.
Click to expand...

Sounds like it could be something with either the Thunderbolt Display or the Thunderbolt Port on your machine?

Do you happen to have another machine with Thunderbolt or a friend who has one that you could test the display with?
 
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