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high CPU usage

  • 51 svar
  • 152 har dette problem
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  • Seneste svar af kimbakat

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after updating to firefox 29 and then 29.0.1, the cpu usage that firefox are using are insane,

it ranges between 50%-100% cpu usage.

and it happens even on normal non flash tab,

besides even if the site is using flash, i am using flash block and adblock plus,

so anykind of flash material wont play or uses cpu.

please fix this ASAP, because firefox has now gone from useable to resource hog,

oh and i don't like the new look, because firefox has become more similar to chrome on User interface,

and i don't use chrome, because i don't like the UI, and now firefox tried to be chrome twin ?

i think that's all, thanks in advance.

edit : fixed some typo

Ændret af DM789 den

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i agree with what you are suggesting,

but you might want to simplify your suggestion,

because at first its clear, but from the middle it became too complicated for average user to understand what you are trying to say.

and i kinda confused by your reply, but it is probably because i have a bad stomach ache (something i eat caused it), and can't think straight.

so should i mark it as solved ? or you would do it and then do what you wanna do with this thread ?

oh btw, the firefox ram usage is kinda high with only 2 tab open, is that normal or not, btw the firefox RAM usage is 310KB, with only the gmail and this tab opened.

Comment from a forum moderator ~J99 I will mark this post as the solution to the thread.

Anyone with similar problems

  1. Please see my summary comment here
  2. Use this special link if you need to start your own question


  • Look at the first page for posts answering the part of the question relating to Firefox appearance
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Alle svar (20)

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Don't think so, but check your task manager, it maybe the Adobe Flashplayer plugin chugging up the CPU

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its not adobe flash player mine is fully up to date its firefox itself doing it as it just starts using cpu up then the memory spikes and you have to shut it down in task manager

first I was figured it was the adblock problem but even with that disabled to it was fixed it still happened I am doing bad today only 5 force closing today I am very close to changing browsers as right now firefox is not usable for long periods

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Managing Firefox CPU Usage [Firefox 31.0, running on Windows 8.1 Pro]].

Here is the configuration of Firefox 31.0 that keeps my CPU usage to a minimum. The background: Firefox was using up to 45% of my CPU even when minimised. I put it into Safe Mode and established that the usage went down drastically, to around 15% or less, and around 5% or less when minimized. Then I started it normally and ensured that I only enabled those that I really need or like out of the long list of addons that I have accumulated. I am very pleased with its performance now. It remains easily the best browser out there.

Typical Firefox CPU usage with 30 tabs open:

Minimized: < 5% Window open: Typically < 20% with Adblock Plus, Flashblock, and NoScript operating everywhere.


Adblock Plus HTTPS-Everywhere DownThemAll FlashBlock Internet Download Manager integration module for Mozilla LastPass Lightbeam NoScript Session Manager Stylish

Plugins: All set to "Ask to Activate" except the following, which are set to "Always Activate":

Java(TM) Platform SE 8 U5 NPLastPass Shockwave Flash

Appearance: LavaFox V2-Green (Zigboom Designs), with about:blank - Orion's Belt and about:home - Orion's Belt.

So there is at least one very satisfied customer.

J M Ward

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It's not the old memory leak problem this is new I did all you said before I updated to the new version this is something new

I have opened with and without extensions and bang after a while the cpu is pushing 90% and the memory is over 1 million going on 2

if there is not something done soon I am going to have to give up firefox I have already started using chrome more but I cannot have a browser that I have to force close 10 times a day

funny thing is it seems to be ok most days between 10pm and 1am which I find strange

I have even done a full reinstall of windows on my pc and when I opened firefox after in its default state it still did it

Ændret af katep99 den

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I just downgraded to Firefox 26.0. I think this was the last stable version of Firefox for my Windows XP computer. I have all my add-ons enabled. Let's see what happens.

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where did you get the old version from till its fixed might be my best option

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My starting point was here: https://support.mozilla.org/en-US/kb/install-older-version-of-firefox

I took my actual download (for Windows) from here: https://ftp.mozilla.org/pub/mozilla.org/firefox/releases/26.0/win32/en-US/

Right click the link "Firefox Setup 26.0.exe" and select "Save link as". Select a location on your hard drive (if Firefox is set up to do so) and execute the file from Windows Explorer.

If you have not set up Firefox to ask for a download location, you can click Tools->Options, select the General tab, then click "Browse" to find out where Firefox will save your download files. In my Firefox version the default location was "My Documents\Downloads".

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Note that Firefox does not acknowledge there is a problem with high CPU usage, so I don't think the fix will be "on its way" anytime soon.

In Version 30 notes, the "Known Issues" are as follows: https://www.mozilla.org/en-US/firefox/30.0/releasenotes/

Errors loading scripts inside eval scripts with Developer Tools open (998908)

Mac OS X: cmd-L no longer opens a new window when no window is available (1008793)

Slow shut downs lead to 'Firefox is already running' warning (see 966469 and 985655) unresolved

Without affecting security, after restoring your session, Extended Validation Certificates might not display (See 995801)

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Here is the state of my system a couple hours after installing Firefox 26 (see pic). Note that I have all the add-ons and CPU is 0%. Of course, Firefox will jump to high CPU whenever you click a link or use the menu functions. This is normal, and it should quickly come down to something less than 10% unless you are buffering streaming content. I tested this with a youtube video. It jumped to about 25% CPU while it was buffering the video content, then went down to about 3% while the video was playing.

Please note that this is not a final solution. It would be nice if someone from Mozilla would post here when they have a solution for this problem so we can get back to the proper upgrade path.

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Sorry, downgrading to Firefox 26 did not help. CPU hovered at about 55% for a while before jumping to 99% again. So 1/2 hour ago I was fine, but now at 99%. So this is a pretty quick failure mode. One good workaround, however, is to restart Firefox. I added the Restartless Restart 9 add-on which adds a restart option to the Firefox "File" menu item. This restarts Firefox and restores all tabs automatically. I will go back to version 30 and restart Firefox every hour or so. This is really bad news for Firefox. I have been a Firefox fan now since version 3. I have already loaded Chrommm on my Linux machines to overcome the Adobe Flash upgrade issue. Now it looks like I will need to do the same for my Windows machines.

Linux: Chromium Browser with Pepper Flash upgrade Windows: Google Chrome

Here are some other alternatives: http://liliputing.com/2014/05/unhappy-chrome-firefox-alternate-web-browsers.html

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My problem seems to have gone away...

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did you try the Nightly versions? http://nightly.mozilla.org/

this did the trick for me more noticeably and consistently than anything else i tried. my response posted on pg. 1:

i have been testing the Nightly versions (now 33.0a1) and the CPU% has been much lower. with the same pages loaded, same add-ons, same prefs, everything. after launching and all pages finish loading the Nightly runs at around 25% CPU vs. about 75% for FF 30.

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I'm running Chromium for Windows now. Idle CPU time is 0%. I imported my favorites from Firefox. Chromium for Windows also has add-ons just like Firefox. I have add-block and WOT, and will be adding others which do the same tasks as the add-ons I had in Firefox.

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I am starting to wonder if it might have something to do with me having vista maybe its just not stable on vista

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OMG katep99! You're one of the dozen people on the planet still running the Vista disaster? No wonder you've got problems. Do yourself a favour and either upgrade to Windows 7 or start using the free and excellent Linux Mint 17 Qiana.

Having said that, it is unlikely that your browser problems are down to Vista. Strip Firefox right down to the basics and try again. To do this, open a command prompt (cmd.exe in the Start box) and type the following line, complete with quotation marks in the positions shown:

"C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -p

You will get the Firefox Profile manager. Create a new profile, called e.g. "Kate", and start Firefox with it highlighted.

Now see if Firefox runs OK. If it does, start reintroducing things gradually. If you use Firefox Sync, disable all your addons once it's synced, and turn them on one by one.

If "bare" Firefox still doesn't run OK, uninstall it completely, including all your user data, using Revo Uninstaller Free in its most aggressive mode - this will clear Firefox keys from the registry. Then reinstall Firefox from a clean installation file, the latest version (31.0).

If that doesn't work, follow paragraph one.

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Why are people using old versions of Firefox? Everyone should be using the current version, Version 31.0, or else your complaints about bugs mean very little.

I have just completed a set of tests on Firefox and Chrome. I uninstalled both, and their associated data, completely using Revo Uninstaller, so even the registry keys were removed. Then I did fresh installations of Firefox 31.0 and the latest Chrome.

With absolutely the basic minimum installed on each browser (i.e. Flash and very little else), I tested each one independently with two web pages open, the Octane 2.0 browser tester start page and the Formula 1 Sports Page from the Guardian (just so you know). I used the Windows 8.1 Resource Monitor to measure the average CPU usage over one minute by each browser, in both the minimised and open-windowed state, after being allowed to settle down. The averages over four results each are as follows:

Firefox 31.0 Average CPU Minimised, 2 tabs: 0.6% Window open, 2 tabs: 2.3%

Chrome Average CPU Minimised, 2 tabs: 3.8% Window open, 2 tabs: 4.3%

This convinces me of three things. One: there is no CPU resource bug in the basic version of the current Firefox, 31.0. Two: Basic Firefox and Chrome perform very similarly. On these results, Firefox seems slightly better. For some reason, Chrome runs several chrome.exe processes at once, while there is only one Firefox process.

Three: Any CPU usage problems encountered are therefore likely to have been introduced by a specific add-on or add-ons, or a plugin, or an Appearance theme or style. I suggested to katep99 above how that might be addressed - use Firefox Profile Manager to create a new profile from scratch, or completely remove Firefox and all related data and start again.

Finally, just for kicks, I did some comparative benchmarking between Firefox and Chrome using the well-established tools Google Octane 2.0 (http://octane-benchmark.googlecode.com/svn/latest/index.html ) and FutureMark PeaceKeeper (http://peacekeeper.futuremark.com/ ) . I used the minimal browser configurations as above. Scores are averaged over four trials.

Peacemaker Octane 2.0 Chrome 1809 6757

Firefox 1822 7224

Both browsers have similar performance; oddly, Firefox's is better on Google's own test! However, subjectively it seems to me that Firefox is quicker to open new pages.

The performance of Firefox will inevitably be reduced by add-ons. However, several of those add-ons, including the LavaFox Green skin (appearance theme) add-on, are very dear to me, and I consider Firefox's one-click bookmarking system second to none.

I therefore declare Firefox 31.0 my overall personal winner.

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Going to get a new gaming rig at xmas that I am saving for then this one will just be for internet use but never really seen the need to update plus cost was an issue till a while back

on the new profile done that no good also done a full reinstall of the pc so done a clean install and still no good

Ændret af katep99 den

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jmward: When this topic was first posted version 31 did not exist. My Windows XP computer automatically updates my Firefox version, so as I was getting more and more updates, the problem still prevailed. But, yes, you are correct. We are all stupid because we do not upgrade to the latest quad core computer running Windows 8 with the latest version of Firefox with no add-ons. Personally, I joined this forum to try and find solutions to problems that people are having IN COMMON to my own issues, not to try to convince them that there is not a problem. Obviously, if everyone had the same problems, it would be highly motivational for Mozilla to fix those problems, but here we have a group of people with specific issues for which WE are trying to find a solution. So, with 30 years of experience writing software myself, I can tell you that the first step to solving any problem is to be able to duplicate the problem. So, until you have duplicated the problem on your own system, your comments about this bug mean very little.

Ændret af jrh_engineering den

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jrh_engineering & Everyone

Thanks for all the posts. This is a subject needing attention and causing problems.

Background Info

No one is saying run Firefox with no addons; or run it in safe mode, day to day. Addons are a great feature of Firefox. What we need to remember is Firefox is highly customisable multi OS multi platform. Also you need to stay on the latest version of Firefox, but don't forget that supports XP even though MS & IE does not.

It is a good point that there are real problems. The first thing we need to do if it is a Firefox bug is to define the problem in the simplest possible terms and circumstances with Steps To Reproduce, and then the developers have something to work with.

If the problem is one you or anyone needs a solution to personally, then start your own threads including full troubleshooting information.

There are various known issues some of which may have been resolved in some of the more recent or pre release versions of Firefox. Some of the issues are seen on older hardware and XP but not on the latest stuff, but even so if it is a Firefox regression exposing or causing the issue there should be a Firefox fix possible.

Testing Unfortunately, and I know this is to say the least inconvenient for end users of Firefox if we really want to get any bug tested and a bug filed properly it must be tested with the current Release, and additionally someone is going to then need to test it with the very latest pre release (The Nightly) .

Anyone interested in the more technical information or the other recent major threads look also at my post in

As has probably been mentioned easy problems get reported and fixed quickest. At the other extreme if you have a problem that others are finding difficult to reproduce you are going to need to do more of that testing yourself and it would be really good to test doing all this at once

  • A clean reinstall of the current Release.
  • A clean new test profile.
  • In Firefox's Safe Mode.
  • With all plugins disabled (Or all but FlashPlayer if it is for instance a problem only when Flash is used - Test first with Flash disabled for comparison)
  • In the OS safe Mode

What can you do about it If you wish to keep using Firefox.

Anyone looking for a solution themselves and willing to provide full information. Or anyone wishing to investigate this further start a new thread also follow the other tips that help bring this matter to the attention of Mozilla.

  1. Please do not post in this thread to ask for a solution
    1. Instead please use special link
    2. Please try to follow the prompts and include troubleshooting info when you do that. (There is a green button to automate the process. Use that, or if you encounter problems doing so mention that in the new thread.)
    • The special link is fast as it cuts out some steps and helpers will recognise that you have seen this thread already.
      It ensures you get advice best suited to your individual problem
    • Note this thread currently
      38 replies, 72 have this problem, 2235 views.
  2. Vote on this thread so that it is noticed.
    Use the button [I have this problem too]
  3. Use feedback input.mozilla.org/feedback
    • I suggest make only a short comment about single subjects
      Otherwise it is likely to be lost in noise as a general complaint.
    • Statistical information from input feedback is made available to developers.
    • Anyone can see & filter the comments in an interactive webpage dashboard input.mozilla.org
  4. Turn on telemetry See Share data with Mozilla to help improve Firefox
    • Most of the data is unlikely to mean anything to average users (or me ) but:
      To view your own data use about:telemetry (key that into the addesssbar)
      Note results of aggregated data is available publicly here telemetry.mozilla.org in another interactive dashboard

I will tag this thread as escalate and when time permits someone from the profession full time HelpDesk will look it over, but that may take a few days.

P.S. Obviously scroll through this thread to read advice and links & do not forget the basic advice articles

Ændret af John99 den

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Hi DM789, Sorry you have been having problems. I hope we have not been overlooking your problem amongst the other posts. You have not posted for a while. Are you still looking for help ?

What is your position with this at the moment please.

These threads are intended to be about single user's problems, your problem.

  • Have you now tried with the current Firefox 31 ?
  • If not you are not using a supported version of Firefox, and if it is an old version there are security vulnerabilities.
  • Do you still have problems ?
    • If you do still have problems do you wish to try and troubleshoot those problems ?
    • That may entail testing Firefox in safemode and with plugins disabled etc would you be prepared to give that sort of thing a try ?

This thread is degenerating into a general discussion of Firefox problems. That is not the purpose of the forum If you are no longer wishing to troubleshoot the problem we may as well close the thread and accept your installation of Firefox as used and installed has problems that are not likely to be resolved immediately or on this forum.

if you are still needing help then now would be the time to post again with an update on your situation because I have just escalated your question thread.



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