cancel
Showing results for 
Search instead for 
Did you mean: 

Firefox is hoging 97% cpu cycles all the time.

SOLVED
Highlighted
New Contributor

Firefox is hoging 97% cpu cycles all the time.

Recently(like today) Firefox has started hogging cpu cycles causing responses to be very s-l-o-w Smiley Sad

Have scanned with Sophos AV and Windows Defender and there is no indication of malicious program activity.

Firefox process remains running even when browser has been closed.

1 ACCEPTED SOLUTION

Accepted Solutions
Site Moderator

Re: Firefox is hoging 97% cpu cycles all the time.

29 REPLIES
Site Moderator

Re: Firefox is hoging 97% cpu cycles all the time.

New Contributor

Re: Firefox is hoging 97% cpu cycles all the time.

Thank you,

I removed 8 older versions of Java console this reduced the memory used from over 500MB down to a more acceptable 150MB ish disabling Java quick start fixed the problem completely and reduced memory usage further to 67MB and bringing cpu usage right down to low levels .

Smiley Happy Smiley Happy
Site Moderator

Re: Firefox is hoging 97% cpu cycles all the time.

You're welcome

New Contributor

Re: Firefox is hoging 97% cpu cycles all the time.

I have this same problem too, much higher CPU usage, and SLOOOOWWWW, even when my activity monitor shows Safari with more windows/tabs open, and using more memory! Many Google searches or sites simply won't open at all!

I'm on a Mac, so it's not just a Windows issue...

New Contributor

Re: Firefox is hoging 97% cpu cycles all the time.

I have this same problem too, much higher CPU usage, and SLOOOOWWWW, even when my activity monitor shows Safari with more windows/tabs open, and using more memory! Many Google searches or sites simply won't open at all!

I'm on a Mac, so it's not just a Windows issue...

Plus, as for Java & Flash, when I clicked the Update link, it told me I urgently must upgrade Flash (although I HAVE the most up-to-date version), and to also update Java, (which I also HAVE the most current one), so where's that leave me???

New Contributor

Re: Firefox is hoging 97% cpu cycles all the time.

I've been experiencing this cpu hog situation of firefox for quite some time. It appears to be related to sites which utilize flash. Because until a site is loaded which contains flash, there is no cpu issue. But once the site is loaded (and I've found this to be true with every site containing flash), the cpu usage jumps to roughly 100%. Even after the site is closed (by closing the tab or even the window) as long as firefox remains running the cpu usage will not drop below 100% again.

Many have said this is an adobe flash issue. Others have said it is a firefox issue. What I do know is that I have both the latest firefox and latest adobe flash player and it happens. When I use IE, the cpu usage even with multiple flash sites open never goes above 25% and once the site which contains the flash is closed IE cpu usage drops down to almost nothing. I really prefer the flexibility of firefox with respect to addons, but until this cpu usage issue with flash and firefox is resolved in some fashion, I have no option but to go back to IE as a browser.

New Contributor

Re: Firefox is hoging 97% cpu cycles all the time.

My problem was as remedied above, by removing Java Quickstart and excess Java consul extensions.


I have never trusted flash, I use prefbar http://prefbar.tuxfamily.org/ which has a simple flash enable/disable check box and (although I have never needed to use it) a Kill Flash button. It also enables the on the fly changing of many other settings

New Contributor

Re: Firefox is hoging 97% cpu cycles all the time.

I don' t have Java quickstart, & have only a single Java embedding plugin (which the Update function keeps telling me is outdated, which it is not, as the Java website even says that Apple has there own Java, and the one I have is the most up to date. Also, I use FlashBlock, so I don't have flash activity going on anywhere but when & where I want it, yet still FF stalls & hogs memory..

This problem has been a nagging one for quite some time, & the other is (as a consequence) I keep getting error windows about a script halting forward progress, & do I want to stop or continue it's loading. Of course, I click Stop, but it still stalls, with the spinning blue ball! Plus, it pops this message up even when I open an empty tab, or even leave Mail, and just come to an already opened FF page! Very frustrating to say the least...

FF_CPU_USAGE.jpg
New Contributor

Re: Firefox is hoging 97% cpu cycles all the time.

I got to the point that Firefox 3.6.11 and 3.6.12 and beta 4.07b ground my PC to a halt for two days with 100% CPU usage and 400+ MB of memory usage. I tried all the suggestions of turning off Flash and Adobe and Java--even turned off my antivirus, but nothing helped. Then I found the cure. I realized the one thing in common between all these versions was my profile.

First, I backed up my bookmarks. I also made print screen backup copies of my site passwords. Next, I uninstalled Firefox but allowed it to keep my profile (i.e., do not check the box that offers to remove your settings). I went into my documents and settings folder, then applications, then Mozilla, then Firefox, then Profiles. I found the profile with extension "default" and added an extension of ".old" to it.

Then I downloaded a fresh copy of Firefox, allowed it to create a new profile. I made a backup copy of the new profile.

Then I followed the directions on this page:

http://support.mozilla.com/en-US/kb/Recovering+important+data+from+an+old+profile

to retrieve my passwords and form history. You can also retrieve your bookmarks, but since I backed up my bookmarks before uninstalling Firefox, I "restored" my bookmark backup through the bookmarks menu. I copied each of the folders necessary for passwords and form history into the newly installed Firefox profile.

Then, total joy. Firefox and I are friends again. I have all my plug-ins/extensions running, am using tabbed browsing, leave Firefox open, and no more CPU hog!

Hope this helps!