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

troye · Jun 27, 2012

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.

GGJstudios · Jun 27, 2012

troye said:
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.

Kernel task is your operating system.

Launch Activity Monitor
Change "My Processes" at the top to "All Processes"
Click on the CPU column heading once or twice, so the arrow points downward (highest values on top).
Click on the System Memory tab at the bottom.
Take a screen shot of the whole Activity Monitor window, then scroll down to see the rest of the list, take another screen shot
Post your screenshots.

troye · Jun 27, 2012

GGJstudios said:
Kernel task is your operating system.

Launch Activity Monitor

Change "My Processes" at the top to "All Processes"

Click on the CPU column heading once or twice, so the arrow points downward (highest values on top).

Click on the System Memory tab at the bottom.

Take a screen shot of the whole Activity Monitor window, then scroll down to see the rest of the list, take another screen shot

Post your screenshots.

Here is the screen shot

GGJstudios · Jun 27, 2012

troye said:
Here is the screen shot

Read step #2 again. It's in bold text.

troye · Jun 27, 2012

GGJstudios said:
Read step #2 again. It's in bold text.

sorry about that.

GGJstudios · Jun 27, 2012

troye said:
sorry about that.

Everything looks normal to me. It doesn't look like anything should be contributing to performance problems.

TyroneShoes2 · Jun 27, 2012

troye said:
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...

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.

aismaiil · Aug 1, 2012

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

GGJstudios · Aug 1, 2012

aismaiil said:
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

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.

TweakOnline · Jan 22, 2013

Guys, is this normal?
On my 15'' MacBook Pro Retina Kernel Task uses more than 1GB of ram, why!?

gnasher729 · Jan 22, 2013

TweakOnline said:
Guys, is this normal?
On my 15'' MacBook Pro Retina Kernel Task uses more than 1GB of ram, why!?

Because you have plenty of RAM, and if it isn't used, it is useless and you might as well not have it.

TweakOnline · Jan 22, 2013

gnasher729 said:
Because you have plenty of RAM, and if it isn't used, it is useless and you might as well not have it.

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... :/

GGJstudios · Jan 22, 2013

TweakOnline said:
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... :/

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

phalgun27 · Feb 8, 2013

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

LPZ · Feb 8, 2013

phalgun27 said:
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

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.

phalgun27 · Feb 9, 2013

LPZ said:
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.

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

phalgun27 · Feb 9, 2013

LPZ said:
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.

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

LPZ · Feb 9, 2013

phalgun27 said:
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

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.

phalgun27 · Feb 9, 2013

LPZ said:
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.

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

phalgun27 · Feb 9, 2013

LPZ said:
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.

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

thekev · Feb 9, 2013

TweakOnline said:
Guys, is this normal?
On my 15'' MacBook Pro Retina Kernel Task uses more than 1GB of ram, why!?

It's because the OS has become bloated in recent versions. It may sound silly, but that is basically the problem.

phalgun27 said:
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.

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.

phalgun27 said:
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

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.

phalgun27 · Feb 9, 2013

thekev said:
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.

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

----------

thekev said:
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.

I am unable to run AHT on my Mac. There is no apple store at my place.

thekev · Feb 9, 2013

phalgun27 said:
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

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.

phalgun27 said:
I am unable to run AHT on my Mac. There is no apple store at my place.

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

LPZ · Feb 10, 2013

phalgun27 said:
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

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?

phalgun27 · Feb 10, 2013

LPZ said:
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?

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)

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

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