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Firefox (3.6.10) is very sluggish/slow and hangs up

New Contributor

Firefox (3.6.10) is very sluggish/slow and hangs up

All of a sudden Firefox (3.6.10) is very sluggish/slow and hangs up

I've been using Firefox (very actively) for over a year now and all of a sudden (yesterday) it began to act very sluggishly. On sites I have always visited frequently it hangs up for periods of 15-90 seconds or more, won't scroll down, won't open hot links, slowly opens new tabs ...

I rebooted my PC (multiple times), powered down my modem and router, ran a Norton disk optimization - essentially making sure it was not an outside factor effecting Firefox's performance. (Note: I am using a cable connection.)

I then ran a side by side speed comparison with Internet explorer (on my 2nd monitor) going to the same web sites, and IE had no problems/hang-ups.

FYI I only have a couple of add ins/extensions (Java, Microsoft Framework, Norton, No Squint, & RealPlayer) and none of those are new within the past few weeks at least.

Any ideas on what could be causing this? How to fix? (As I much prefer Firefox to any Microsoft product.)


Site Moderator

Re: Firefox (3.6.10) is very sluggish/slow and hangs up

Create a new profile as a test to check if your current profile is causing the problems.

See Basic Troubleshooting: Make a new profile

There may be extensions and plugins installed by default in a new profile, so check that in "Tools > Add-ons > Extensions & Plugins"

If that new profile works then you can transfer some files from the old profile to that new profile (be careful not to copy corrupted files)


New Contributor

Re: Firefox (3.6.10) is very sluggish/slow and hangs up

Oh for the love of cheddar, I am getting sick of this non-answer. Every problem with Firefox's shoddy memory management post FF3 get this standard "it's your fault not ours" drivel.

Firefox is now a slow, memory-hogging chunk of garbage. It's not the profile, it's not the plug-ins, it's not the add-ons, it's not the extentions, it's firefox itself.

Go to google, type in "firefox sluggish" or "firefox memory hog/leak" and you will get tens of thousands of posts about this. I personally have Firefox on three computers at home, two computers at work, and one computer at my brother's house, every one of them has this crappy, sluggish, memory hogging performance--ever since Firefox 3.anything, to be specific. Windows 2000, xp, vista, and 7, all the same issue.

Sitting here and blaming the extensions over and over is not addressing the problem that Firefox is not garbage. It will take up more and more memory until every input has a 5-30 second delay, and don't sit here and tell me "that's how Windows uses the memory now. It's not: I use Opera, Chrome, Safari, and IE to test websites, and none of the other browsers have this issue.

I love Firefox, I love the customizability, but the basic program is broken, and has been for some time. You people can harp on add-ons and blame the end user all you want, but as it stands, I have to use other browsers if I want to get anything done, and the second Google starts releasing some add-ons that do similar things, Firefox is history. It's pathetic that IE performs better now.

So when someone (or, specifically, 43 people at the time of this post) brings up a problem with the newest revision of Firefox, don't immediately tell them its their settings when you know different. The only common strand we all have is that we are all using Firefox itself--the program is broken.

Fix it.

New Contributor

Re: Firefox (3.6.10) is very sluggish/slow and hangs up

@senselocke: same problem i encountered also... but just a while ago i installed back my old rambooster program, and all is well..for now maybe.. it's worth a try.. i'll post a reply again if it fails though...

rambooster can be found here...

New Contributor

Re: Firefox (3.6.10) is very sluggish/slow and hangs up

Yes, FF gets sluggish from time to time. Sorry but it's the fact! FF also cannot render some websites properly (especially v3.6.10). I'm a big fan of all Mozilla software but FF 3.6.10 makes me very disappointed.

New Contributor

Re: Firefox (3.6.10) is very sluggish/slow and hangs up

Completely agree. There's a solution called "voting with one's feet."

New Contributor

Re: Firefox (3.6.10) is very sluggish/slow and hangs up

When Firefox self-updated to 3.6.11 it went from being relatively easy and reasonably quick to load to becoming completely non-functional. It hangs and does not completely load. I've had to switch to Chrome and for some non-compliant commerce sites I've even been forced to use Explorer (egads!).

I tried uninstall/reinstall with no better result.


New Contributor

Re: Firefox (3.6.10) is very sluggish/slow and hangs up

Hey ya "senselocke" ... you are absolutely correct & spot on ... what Firefox advises is 99% similar to any "tech customer service" ... have the user chase a carrot JUST to ignore the issue.

Firefox was the best browser ... what I think went wrong is they let all these plug ins come into play VERSUS just having Firefox handle all the new technology ... all these new plug ins while may work ... they have rendered the basic Firefox browser almost useless without them. Hope I made sense.

I agree with you 100% ... and long live the cheddar.

New Contributor

Re: Firefox (3.6.10) is very sluggish/slow and hangs up

Hi, sadly this problem is still present not only in the latest stable release (4.0.1), but also in 5.0-beta2 and in 6.0-alpha versions of Firefox. but the WORST part is, it seems this sluggishness / stalling / freezing / hanging / stuttering - whatever you call it - concerns ALL GECKO BASED web browsers. and I mean literally all, regardless of the implementation. I even took a liberty to do a simple benchmark. the applications I checked and confirmed having this issue are as follows:

  • Firefox 3.0.19, 3.5.19, 3.6.17, 4.0.1, 5.0-beta2, 6.0-alpha1
  • SeaMonkey 2.0.14, 2.1-rc1
  • K-Meleon 1.5.4
  • Conkeror 0.9.3 (even Conkeror suffers this a bit, especially while scrolling pages and writing text into edit fields)

these all were the default installation, using no extensions, just the standard Mozilla addon, without JRE and Adobe Flash installed. the platforms used to perform the tests were

  • Windows XP x86 SP3 Home/Professional(hardware used: H1/H2)
  • Windows Vista x86 Home Premium(H2)
  • Windows 7 x86 Home Premium(H3)
  • Ubuntu 10.10/11.04 i386 (H1/H2/H3)

my hardware:

  • H1: Asus A8N-E, AMD Athlon64 3200+, 4GB DDR400, GeForce 7200, Seagate HDST3500413AS
  • H2: Toshiba Satellite A300 (stock)
  • H3: Toshiba Satellite A500 (stock)

additionally on the same machines I tried Opera 11.11, and SRWare Iron 11.0.700.2, and found no such issue in both these cases. I visited sites like facebook, youtube,,, vimeo, google docs, ebay,,, and many others (I did not standarize here too much because my main concern was the interface performance not the web browsing performance). in concluson. I do not think the is something especially wrong with firefox per se.however the very core of the application, that is shared with other web application, the xullrunner/gecko engine, could be very much to blame.

of course I advise everyone having the issue with Firefox to do your own benchmarks and see if you can get to the similiar conclusion. I hope this issue will be dealt eventually. Mozilla has done so much good work for the free internet community as of this day. I am sure they have some good reasons why this issue have not been resolved yet. maybe the hardware they use are like 10s or 100s faster than the user's, so they cannot experience the sluggishness of their own product =P btw. I forgot to mention the latest Thunderbird, which also has the built in web browser and of course suffers the issue. I hope I somehow helped, cheers

New Contributor

Re: Firefox (3.6.10) is very sluggish/slow and hangs up

I've had this problem too. It seems to be solved now.

I found a discussion about Flash, and that the software does not do a good job removing old versions. I went to the Flash site and downloaded the Flash removal tool, then installed the latest "Firefox" version (not the IE version).

I also removed and re-installed Java, but I don't think that was an issue.

As soon as the latest, and only, Flash was installed Firefox seemed normal.

Hope this helps someone.


Tom C