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Firefox is unbearably slow after updating to version 27

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  • 606 有這個問題
  • 22 次檢視
  • 最近回覆由 petef

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After updating to Firefox 27 all webpages take a few dozen seconds to several minutes to load. When loading a webpage Firefox's status displays "connecting" and the CPU gets maxed out with 95 to 100% of its cycles taking by Firefox.

The computer is older so it is a little slow but Internet Explorer 8 has no trouble opening the webpages and neither do other computers on the LAN so it is not a network issue. I have tried restarting Firefox, disabling add-ons, deleting add-ons, disabling hardware acceleration, restarting the computer, and reinstalling Firefox after wiping every trace of it and its user data from the hard drive and registry.

CPU: AMD Athlon 2800+ 2.08GHz RAM: 1GB OS: Windows XP Home Edition Service Pack 3 32bit

Comments by a forum moderator.
(Modified April 30, 2014 12:11:58 PM BST by John99 ) ~J99
Rather a long thread so I will add some comments here where easily seen.

 Modified June 18, 2014 6:08:41 AM PDT by John99

由 John99 於 修改

所有回覆 (20)

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I downloaded 27 from here as they still showed it as available - but be quick as it might go soon.


EDIT I would advise against using unsuported versions of Firefox.
I would advise strongly against using downloads from unoficial sites and have prevented the above link from displaying. Please see the article

I just did an install and it overwrote 28 and got me back exactly where I was this morning before the automatic update. It gave me 27.1 which seems OK without deleting Cairo.

I have now turned off automatic updates.

由 John99 於 修改

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Mozilla can not recommend that you use ESR. That is intended for use by organisations and not individuals, but although it is not supported for individuals to use you will note that it is secure because it gets security upgrades. ESR is currently based on Fx24

Anyone wishing to use it in a corporate environment see

Others may be aware of a unofficial builds installable as standalone additional browsers

The bugzilla bugs are a working place for developers and not a discussion forum. As mentioned upthread there is an open bug on this subject. It may be appropriate to update that bug to mention

  • The workaround no longer works with Firefox 28
  • Link to this thread
  • Confirm details of the hardware on which this problem is seen
  • Possibly ask in the bug if it is appropriate to update the existing bug or open a new one.
  • Please restrict comments to adding essential information https://bugzilla.mozilla.org/page.cgi?id=etiquette.html
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Thank you. Sorry I didn't get back sooner, been away.

In the end I downloaded Firefox Setup 27.0.1.exe from https://ftp.mozilla.org/pub/mozilla.o.../en-GB/ and ran it.

This appears to have successfully "downgraded" Firefox to 27.0.1 and did not overwrite my settings.

Working again now. No more updates until bug is fixed.

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Personally in your position I would have opted for Fx24 ESR because although not an official Mozilla recommendation at least it is secure. i is of course your decision as to what you install and run.

Bug 973149 - Animations cause CPU Kernel mode overhead is not something that affects me an so it may be inappropriate for me to comment in that bug. It is likely to be low priority if it only affects XP, especially given the EOL position.

Th priority of the bug may be increased if comments are added that

  • it is a Firefox regression (Normally added as a keyword regression)
  • it now has no workaround (IF that is now the case in Firefox 28)
  • Others start votingv=for and CC ing themselveson the bug (Votes may not have a direct impact but do show there is an interest in the bug being fixed.)
    • Vote by using the checkbox, not by adding metoo comments. Note an email address will be required and will be made public. (I have just doubled the number of votes !)
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Thanks John99. I'd never heard of ESR, I'll try it. Is 'Fx24 ESR' SYNC compatible with Fx28 on Android?

Commenting/voting etc not possible on bug report without a bugzilla account, probably accounts for low votes as most with level of expertise will not be running on XP! (there are many of us out here still on XP as not all m/cs capable of running W7 or 8, or have XP dependant software).

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As of Firefox 28, the problem appears to have disappeared, although I cannot yet say for certain if it is really gone for good or has merely temporarily relapsed as before

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Firefox ESR is sync compatible. You will not have heard of it as it is not intended for ordinary end users, it is aimed at corporations and educational establishments with their own IT departments.

Personally I consider ESR quite handy occasionally for easily proving a regression exists and as a temporary workaround for the regression. Especially so where a regression affects only some sites or actions so the standard Release may be used for most day-to-day browsing, and the unofficial portable may be used just on the problem sites.

An alternative to Win7/8 at XP End-Of-Life may be to use Linux. Especially if a lightweight distro is chosen. There are options to have a dual dual boot installation allowing you to choose between running old XP apps, or running in a fully secure manner on the internet. The Linux software including something similar and fairly compatible with MS Office is free.

Anyone may open a Bugzilla account, no need to be a developer, but it is asked that it be used as intended to work on the bug fix and not turned into a discussion forum.

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I am not sure now if this problem has disappeared in Firefox 28 as the post by BrokenEye suggests or whether it is still seen in F28 but is even worse; because the fix does not work; as suggested in petef's post upthread

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I believe the only difference between v.27 & v.28 is that the fix that works in v.27 doesn't work in v.28, as summarised by jigobren here:


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That's what I thought, but I do not use XP myself at present. Presumably this also will affect Firefox 29.

I have amended my summary to remind readers of this thread that if they are apparently suffering from the long standing issue that was previously fixable it may be worth voting on the open bug report.

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Is there even an intention to fix this?

I (and most everyone else, I presume) am now on FF 30 and the problem not in any way fixed.

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There doesn't appear to be any progress in fixing it. I have reluctantly given up using Firefox on my laptop.

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Same. I have other machines, but even there's obviously a huge waste somewhere, as the performance difference is more than 10:1 before/after. It's not some beneficial new function, it's something hogging the machine while chasing its tail.

Unfortunately I've got a bunch of stuff saved as sessions instead of bookmarks, so that info is now stranded. I s'pose I can try importing them onto a multi-core machine, but FF will still wedge itself on that one. Do you know of any way of importing Session Manager sessions into another browser? Were I a developer I could write some sort of script, but I have no clue how to do that.

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Hi Atanasoff

It is easy enough to put the sessionstore ie open tabs onto another machine without needing to be a developer. As long as you are able to find and copy files.

If everything is Firefox 29 I guess it would be possible to use the new sync and that should merge the new tabs on all the devices BUT personally I would NOT risk attempting that without backups.

Briefly Find your Firefox profile with Firefox open. Close Firefox & copy the files sessionstore.* . On the fast machine create a new additional Firefox profile. Paste in the file sessionstore.js to overwrite any existing file of that name in the additional profile. Those should be available to use. It is also worth immediatly bookmarking the open tabs. Now (and it is anew profile with no other bookmarks -other than the hand full of default ones) export as html bookmarks. You could even as an alternative transfer the sessionstore files to another working profile but that gets messy and overwrites existing open tabs. The HTML bookmarks may be imported into another Firefox. Note HTML do not overwrite they tag on to other bookmarks. (Do NOT backup and restore Firefox defult .json type or you will overwrite and destroy bookmarks)

If you need detailed help doing that please start a new question (post back here once you have done that )

Related articles

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@Atanasoff Aside John99's valuable answer, it's also very easy to get back to an older working version of Firefox on your older computer. The safest choice is the ESR 24, which you can find here: https://www.mozilla.org/en-US/firefox/organizations/faq/

Download and install over your current unusable Fx 30 (the ESR release benefits from security patches, and it won't try to automatically update to the latest Fx release).

Now Firefox should be usable again. And you can export your saved sessions from Session Manager directly. Have a look at "Exporting Session Files" in this page: http://sessionmanager.mozdev.org/documentation.html

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Windows users also note that the third party Firefox Portable ESR may be worth a try as an additional browser, especially if the problem is only seen on the occasional site.

Note ESR will be updating in due course to be based on Firefox 31 so using ESR only postpones the problem. If the bug is not fixed as a priority then Firefox 31 ESR will not work.

I am hoping that at some stage there will be action and a fix on this bug, and suggest people with this problem vote both on this thread and on the bug.

Other things to help get the problem noticed

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John & Jigebren:

I installed ESR and noticed an immediate relief from the problem, confirming with certainty that it's FF and not an issue local to my machine. But it appears the company has no desire to fix the issue.

tx for your posts on this issue. Regarding exporting, one can copy the session files, but (as I understand it) they only work in another FF install, not in a different browser.

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ESR is not normally intended to be used by individuals it is intended for Companies etc. with their own IT department. It is however a Firefox browser and will use Fire fox profiles and profile files.

You say

But it appears the company has no desire to fix the issue. 

I am nothing to do with the development and engineering work but I think it is more a case of

  • Work needs prioritising.
  • It may not be an easy fix because of what has been removed

My suggestions to help get the problem noticed and possibly prioritised are

  • Vote on this thread as having the problem
  • Comment in output. A very short comment mentioning Firefox is slow and almost unusable. Specifically mention bug 973149
    (Long comments will probably just get categorised and logged as general dissatisfaction)
  • Turn on the telemetry. I am sure the problem will be recoded within those results.
    Send performance data to Mozilla
  • Vote on the bug (see my post upthread)

Potentially Important Work around

One issue is the tab throbber. This is an animation causing problems on every tag you open. This may be removed by hacking the browser Chrome (interface). I will repost this bug comment from spmbox1 (#c18)

I found a workaround

1. In Firefox go to "about:support" address.

2. When Troubleshooting page loads, look for "Application Basics" table, and in that table look for "Profile Folder" and hit "Show Folder" button near it. Your profile folder will open.

3. In the opened "*.default" folder create a new folder and name it "chrome" (remove inverted commas).

4. Open your newly created folder and minimize it for now.

5. Open Microsoft Notepad (windows logo+R type notepad). To the new empty document copy-paste the following line:
".tab-throbber { display: none !important }" (remove inverted commas)
Click "File" - "Save as", name your document "userChrome.css" (remove inverted commas) and save it in your earlier created "chrome" folder.

6. Restart Firefox (close it, wait a minute, and then open it up again).

7. Enjoy.

Now pages load almost instantly, and no annoying throbber (activity animation). After page loads favicon appears as usual.
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For any of the advanced users that are still around and have been seeing this issue various bugs have been fixed and it would be of interest to know how well different versions of Firefox now work.

Some issues will have been fixed in Firefox 31 and that is now the current Release that nearly everyone should be using.

Some of you will have temporarily changed to using an ESR Fx26 the next major upgrade of ESR will be based on Fx31 so it is important to try Fx31 as soon as possible.

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Does 31 fix any of the things 30 ruined in terms of the ugly interface and crippled customization?

由 BrokenEye 於 修改

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