Firefox Consumes the CPU - Comments Page 1

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Posted by:

Joshua Burke
01 Sep 2005

The problem is most likely caused by firefox being paired with a newer version of acrobat reader. If firefox is trying to load the acrobat plugin and: 1) You do not have FF 1.0.x or higher AND 2) You are using the latest version of Acrobat, you can have this problem.

There are 3 solutions available: Upgrade your firefox install, Downgrade your acrobat install to 5.0, or Download Adobe Reader Speedup from here:

Solution 3 kills the plugin loading and seems to work in most instances. I have had 1 instance where this was ineffective. System restore was the culprit but that is beyond the scope of this answer.

Posted by:

06 Sep 2005

I'll go one better; something I've recommended to my friends. Throw any and all versions of acrobat reader off your machine, uninstall it; replace it with a better, faster, far less memory-hogging app.
Foxit PDF Reader. See here:

BTW, I'm still using firebird 0.7 and love it. True, there are a few sites that don't render correctly, which is when I use the fine extension 'Open this page in IE'.

EDITOR'S NOTE: There are some serious security flaws in back-level Firefox versions. I would strongly recommend that you upgrade to the latest version.

Posted by:

07 Sep 2005

I don't think it's solely a problem with Adobe. I have had it happen while on my Yahoo! mail trying to attach a file. If I try to browse to the file and change directories too quickly (while the last bits of the "attach files" page are still loading), CPU usage shoots to 100% and stays there until I Ctrl-Alt-Delete and kill FireFox. No Adobe anything in play. If I am careful to let the page finish loading before I click the browse button, it's just fine. The problem is repeatable. If that page is still loading when I click Browse and try to change directories, it maxes the CPU every time.

Posted by:

07 Sep 2005

I followed these directions, and guess what? IT WORKS. I think it is probably the Windows Memory hack near the end of the story.,1697,1854234,00.asp

Posted by:

11 Sep 2005

I have similar annoying issues with Firefox too. (I love firefox, except for this). Ocassionally, I've left my computer running with Firefox up and running. I come back to the computer, and the computer is churning away like it's tracking down the value of pi... I looked at CPU usage (looking at "processes" in Windows Task manager), and Firefox was taking up an ENORMOUS amount, even it wasn't "doing" anything. I closed Firefox, but even after it had closed, it continued to eat up a large amoung of CPU capacity, although after about 15 minutes it gradually went down to an acceptable level. What gives?!

Posted by:

12 Nov 2006

The exact reason for the 100% memory usage may remain a mystery. However, several things can be considered, including the aforementioned fixes.

First, try uninstalling any extensions you may have and then take notice of your system. A faulty, unstable extension may be causing the problem.

Secondly, depending on the websites you are visiting (i.e. mature and/or inappropriate), they may have a lot of embedded code that attempts to install browser hijacks,trojans,viruses,etc. Firefox will freeze as it is processing and actively declining the requests. Also, a lot of embedded flash objects will also cause firefox to use a lot of cpu time. Try installing the firefox flash stopper extension.

Thirdly, if you use firefox's built in download manager, DON'T. Downloading one or two files at a time is usually fine. You may run into an issue if you download 5+ large files at a time. Firefox will surrender all resources to the download manager and leave your system starving.

There are several other issues with firefox as well, memory management issues and more. I still use it, you just have to minimize the possiblities as to what may be going wrong.

Posted by:

18 Nov 2006

I don't recall ever seeing this except for times when Firefox crashes, or perhaps even some other process. Sometimes you will find in the running processes tab in Task Manager, an image name of dumprep.exe. When I see my system slowed down, that's what I look for, and ending the process makes it all good. Perhaps I missed the point of this post, but then again, maybe there are some that haven't noticed this. Google dumprep.exe and you can find ways to disable the dump reporting that is going on, or just end the process.

Posted by:

John Yanefski
11 Feb 2007

We are experiencing the same problem but it has nothing to do with acrobat or plug-ins. Seems to be purely based on page size and heavy javascript usage. I have page with is used to display a deep (sometimes very deep) tree view of query results. Client-side javascript is used to recursively open/close folders. Trying to open all nodes on a large tree view sends firefox into the weeds. 99% CPU usage. I have the same problem in FF 1.5 and 2.0. I've gotta say this kind of thing sends me running back to IE. :(

Posted by:

02 Mar 2007

@John Yanefski, Do you know if there's any fix for that? it's so hard to browse the web these days with FF crashing on me every 5 or 10 minutes :(

Posted by:

tom sawyer
05 Mar 2007

Installing the flash blocker should resolve the mem problem. 'And people wonder why I'm sticking with Internet Explorer'. Yes go stick with the bug riden, security challange choice. That bloatware didn't change for years until people actually started to use something else. Let's see if this makes it on the site the same way I wrote it.

EDITOR'S NOTE: You post as "tom sawyer" with an email address of "", tell people to solve a browser problem by turning off an important feature that will render many sites useless, and expect credibility?

Posted by:

tom sawyer
06 Mar 2007

You can simply click to say load that item if you want it. In the VAST majority of the cases, it's not wanted or needed. I'll give credit where credit's due, I wasn't sure the comment would make the site but it sounds like someone needed to do a little investigation before making statements.

Posted by:

22 Mar 2007

I have the same problem. except mine roams around. sometimes it's Firefox at 100%, sometimes it's explorer at 100% (the OS interface, not internet explorer) and sometimes it's the task manager itself at 100%! (if I leave it open to see what's causing problems) it is most annoying. And interestingly enough, I too have 1gig ram, and XP SP2.

Posted by:

18 Apr 2007

I have exactly the same problem as novaxe1. 1gig ram, and XP SP2. I noticed this after installing Google desktop search engine, but I really think it is just a coincidence. Still trying to solve it...

Posted by:

Brian Zab
06 May 2007

Both machines I use (XPSP1 and XPSP2) are unable to work right with Acrobat Reader. In fact, I can't remember when it ever has. Symptoms: Firefox at 99% CPU and taking up 200 megs of ram (for a 1.2 mb PDF file). Before loading the file, Firefox averages about 50 megs. After using the plugin, even the fonts folder develops a 30+ second delay, slowing everything down from bolding my text in Word to printing something using Windows API (DOS app printing fast as ever).

Also: complete format and rebuild. First thing I installed was Firefox and AcroRead 8. Perfect reproduction of the problem. PDFs load fine outside of Firefox without side effects.

EDITOR'S NOTE: Try the Foxit reader instead. Works great for me as an alternative to Adobe Reader.

Posted by:

09 May 2007

I'm noticing that svhost.exe is running the processor at 100% with firefox right behind it. Then after "Ending Process" on svhost.exe Firfox jumps to 100%. If I try to "End Process" on firefox.exe (now running at 100%) it just starts right back up again. Reminds me of the old malware issues. Even when it's closed I have this problem (after running it). And ofcoarse if I uninstall firefox the process dies and my PC is back to normal. I refuse to "Disable Java" or run a "Flash Block", I'd rather just not use firefox, as much as I do love it. *note this is not hogging memory but processor cycles, I've seen a lot of posts confusing this.

Posted by:

15 May 2007

Thanks cliff one of the tweeks has fixed this for me, not sure which or which ones since I did a few of them from the page you mentioned href=",1697,1854234,00.asp">,1697,1854234,00.asp

Posted by:

Ras Irafat
20 May 2007

I had the same problem and found help at the above. Here you will get an explanation and how to correct (patch) the problem.

EDITOR'S NOTE: Yes, but blocking all Flash graphics will effectively cripple many websites. Not such a good tradeoff...

Posted by:

12 Jun 2007

Editor, I see that you don't feel it a sufficient trade off to block flash graphics. But as is with these programs, they DO lighten the load on your computer, and as is with these programs, with usually a simple click you can allow flash and java on your selected sites. So if you know a site will need to function with flash, you can easily enable it, and if a site isnt working properly, you can easily enable it to see if that is the problem.

EDITOR'S NOTE: So you click to enable Flash, and you're right back to where you were -- 100% CPU. Nothing solved. (As for your other comments, please refer to A.J. Liebling.)

Posted by:

Jay Simkin
03 Jul 2007

I run XP Pro/SP2, on a Dell with 1GB RAM. Most recent CPU usage rates = 80-100%. Download speeds very slow (I run XP Pro/SP2, on a Dell with 1GB RAM. Most recent CPU usage rates = 80-100%. Download speeds very slow (

Posted by:

11 Jul 2007

So if you're an IE user/lover, how do you solve the same problem with IE? I load IE 7, it comes up and then consumes 100% of the CPU trying to load the home page, it seems. I have to kill iexplore.

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