MBP with 10.6.8: CPU usage high, no responsible processes shown in Activity Monitor. What causes this?

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MBP with 10.6.8: CPU usage high, no responsible processes shown in Activity Monitor. What causes this?

After using my computer for some time, CPU usage climbs to about 90% (ca. 65% user / 26% system) and fans run at high speed, but there is no processes that seem to use CPU (other than Activity Monitor itself ~1%).

This has happened a few times recently. It happens when I've used my computer for some time, hours or a couple of days (I usually put my computer to sleep when not using it but rarely shut it down). I've tried to quit all running apps incl. Growl, Dropbox, and anything that could be responsible to this but with no results. Putting computer to sleep for a long time doesn't help, cpu usage will climb instantly after wake up. Restarting system is the only thing that helps.

Most of the time I use my laptop with external monitor, lid closed and connected to power supply. When experiencing this, opening the lid causes fans to slow down, but CPU usage remains high and battery drains quick.

Any ideas what might cause this?

My MBP is 15" model with Core 2 Duo 2,66 GHz (MacBookPro 5,3), OS X version is 10.6.8, all available updates are installed.

MacBook Pro, Mac OS X (10.6.8)

Posted on Feb 21, 2012 3:05 AM

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Answer 1

OGELTHORPE

Level 9

57,329 points

Feb 21, 2012 4:12 AM in response to Hurja

When you look at the Activity Monitor, on the column labeled '%CPU' (towards the top of the window) have you clicked on that so that it displays the usage from high to low on that column? This should identify those applications that are consuming the most CPU resources.

Ciao.e

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Answer 2

Hurja Author

Level 1

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Feb 21, 2012 5:39 AM in response to OGELTHORPE

Yep, I've sort the processes by cpu usage, but there is really nothing that can explain this. At the time this happens, in process list there is only a couple of processes using CPU at all and no more than a couple percents. At the same time CPU usage meter tells a different story... Also, there was no noticeable disk activity and (iirc) nothing unusual in memory usage.

Beside updates via Software Update, two apps were installed to my computer some time before I first noticed this problem: McAfee Security and AdmitMac. Anyway, according to Activity Monitor, any processes associated with these do not seem to cause noticeable (and constant) CPU load...

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Answer 3

eww

Level 9

53,052 points

Feb 21, 2012 7:42 AM in response to Hurja

Be sure to select "all processes" from the pull-down menu in the Activity Monitor window, or you won't see all the processes that are running. I suspect you've got a runaway process that's not shown under whatever option you've selected up to now.

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Answer 4

Hurja Author

Level 1

0 points

Feb 22, 2012 6:04 AM in response to eww

Thanks eww, this propably helps next time I experience the problem... (I wonder why I didn't see that "My Processes" was selected. *feeling smart right now*)

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Answer 5

ds store

Level 7

30,855 points

Feb 22, 2012 6:57 AM in response to Hurja

Perform a SMU reset. 🙂

https://support.apple.com/kb/HT3964

Remove the anti-virus, it's running a root level process all the time that's taking your CPU and it's not necessary as there are no Mac viruses, Apple has the trojan angle covered already.

Always on anti-virus on a Mac is always a source of problems, also is MacKeeper, uninstall that here if you have it.

http://applehelpwriter.com/2011/09/21/how-to-uninstall-mackeeper-malware/

If you need to clean the Windows filth off PC files, then use the free, run as you need, ClamXav.

http://www.clamxav.com/

It seems your machine is used in a corporate enviroment, thus likely a rule that anti-virus must be used, you can avoid high CPU usuage by using the ClamXav instead.

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Answer 6

Hurja Author

Level 1

0 points

Feb 23, 2012 12:09 AM in response to ds store

It's not my choice to use McAfee. This is company's computer and they require anti virus software to be installed in any computer...

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