Mac OS forum


High CPU usage

by rammatt / September 1, 2011 8:35 AM PDT

Recently i have had very high cpu usage on my mac with very little running. Right now activity monitor says the system is using 67% and i am only running crome and activity monitor. I have a newer macbook pro maybe a month or two old. It is running lion. I have run some legit spyware/malware scans they didn't find anything but im willing to try another program. Also in safe mode the CPU usage is normal. I would like to avoid reinstalling although i do have a lion disk to do so with. Thank you in advance for any help.

Discussion is locked
You are posting a reply to: High CPU usage
The posting of advertisements, profanity, or personal attacks is prohibited. Please refer to our CNET Forums policies for details. All submitted content is subject to our Terms of Use.
Track this discussion and email me when there are updates

If you're asking for technical help, please be sure to include all your system info, including operating system, model number, and any other specifics related to the problem. Also please exercise your best judgment when posting in the forums--revealing personal information such as your e-mail address, telephone number, and address is not recommended.

You are reporting the following post: High CPU usage
This post has been flagged and will be reviewed by our staff. Thank you for helping us maintain CNET's great community.
Sorry, there was a problem flagging this post. Please try again now or at a later time.
If you believe this post is offensive or violates the CNET Forums' Usage policies, you can report it below (this will not automatically remove the post). Once reported, our moderators will be notified and the post will be reviewed.
Collapse -
Clarification Request
So if you use Activity Monitor
by Jimmy Greystone / September 1, 2011 10:32 AM PDT
In reply to: High CPU usage

So if you use Activity Monitor to list processes in order of CPU usage, which one(s) are using the most CPU time?

Collapse -
Activity monitor
by rammatt / September 1, 2011 2:35 PM PDT

Well it has actually been getting better and then way worse and it seems to be random right now it is fine but an hour ago the kernal processes were using like 200% and some crazy amount of memory. So i guess that would account for all the system usage. Do you know what could be making this randomly happen?

Collapse -
A lot of different things
by Jimmy Greystone / September 1, 2011 11:06 PM PDT
In reply to: Activity monitor

A lot of different things could generate kernel_task activity.

I am curious about these "legit" spyware scans you ran, since there's really no spyware/malware for Mac OS X, which would make these allegedly "legit" scans somewhat suspect on their face.

Collapse -
by rammatt / September 2, 2011 2:17 AM PDT

Well I got the scanners from a forum where someone was having issues and they were like computer cleaners too not just malware scanners one was called mac keeper the other was ClamxAV. Also the problem was there before i ran any programs. Also Sometimes when i put it to sleep and wake it up the kernal processes are low and everything works fine, but i would like a concrete solution instead of spend 10 minutes everytime i want to use my computer.

Collapse -
by Jimmy Greystone / September 2, 2011 10:43 AM PDT
In reply to: Scanners

Well, from a cursory glance, Mac Keeper is a scam program. One of those that will do a bunch of really simple things you could have done yourself, only for the low low price of $50 or whatever it is they want for it. ClamXAV isn't a scam, but it also doesn't check for malware last I checked. It's an open source AV scanner, and while I applaud the effort, it's still not even in the same league as commercial scanners.

The fact that safe boot works without issue tends to point the finger at some program starting at login. So go to the user account section of system preferences, then hit the login items tab and see what there is. Then google each one along with "kernel_task" (make sure that's with two e's on kernel) and see what turns up.

Collapse -
Power supply
by rammatt / September 2, 2011 2:15 PM PDT
In reply to: Well

I have tracked the problem down to the power supply because when ever the computer is unplugged from the power supply the CPU goes crazy and kernel tasks go to like 270%. However when connected it runs fine.

Collapse -
by Jimmy Greystone / September 2, 2011 11:11 PM PDT
In reply to: Power supply

No, when you disconnect the ac adapter the OS defaults to a lower power operating mode. So, all you've found is a triggering event that sounds a lot like some sort of OS corruption. At this point I'd say you've run out of options to avoid reinstalling the OS.

Once you reinstall the OS, only install the barest of minimum apps you need for 2-3 days. If you can make due with Safari for a couple of days, even better. Then remember that Spotlight will be indexing your drive for a day or two so if CPU use seems a little high early on that's normal. After 2-3 days, if the problem is persisting, and you've only installed the barest minimum of apps, the problem either exists with one of those apps or there's an issue with the SMC that is much deeper than a corrupted state. You'd need to take your system in for a diagnostic.

Collapse -
Resetting the System Management Controller
by rammatt / September 2, 2011 2:56 AM PDT

so after figuring out that the power adapter not being plugged in the mac is cause the problem i reset the SMC and it didn't help.

All Answers

Collapse -
I had this problem and it turned out...
by f0rtyLeGz / September 2, 2011 8:47 AM PDT
In reply to: High CPU usage

I had this problem and it was driving me crazy. What solved it was quitting Firefox and using Google Crome.

Collapse -
I dont even have firefox
by rammatt / September 2, 2011 2:14 PM PDT
I dont have firefox I uninstalled it because I thought that was the issue but that didn't do anything.

Popular Forums

Computer Newbies 10,686 discussions
Computer Help 54,365 discussions
Laptops 21,181 discussions
Networking & Wireless 16,313 discussions
Phones 17,137 discussions
Security 31,287 discussions
TVs & Home Theaters 22,101 discussions
Windows 7 8,164 discussions
Windows 10 2,657 discussions


Your favorite shows are back!

Don’t miss your dramas, sitcoms and reality shows. Find out when and where they’re airing!