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Firefox 12 is very slow to load pages and if two tabs are opening it lags.

  • 67 replies
  • 511 have this problem
  • Last reply by John99

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Firefox 12 is very slow to load pages and if two tabs are opening it lags. I've tried everything (e.g virus, defrag, I've created a new profile in "run", etc). I've had my router/line etc all checked and after 2 weeks of cleaning/testing etc its all pointing to Firefox as the problem. Please help as it's driving me nuts.

Modified by NoahSUMO

Chosen solution

I've no idea whats happened but I've done a system back up thingy to about a month ago and it seems to be better, I can now open five tabs at one time to games sites in approx 10 seconds which is great. maybe I've done too much fiddling with the system. I think I'll be content with it now and stop bothering you madperson ;-) Next job now is to find out why half my FN keys don't work. Cheers for all your help.

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All Replies (20)

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I switched back to Firefox 11 just because Firefox 12 was so damn slow.

They've been making Firefox for years, so they should be able to upgrade without making the new version practically useless.

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Guys, we all have to admit there is a horrible memory leak in all firefox recent versions and I think 12 is the worst one. I advise everyone here to use this tiny tool. Believe me it'll never let you down. Just bring up your task manager to monitor FF memory usage before and after installing it and see the difference. The tool is FIREMIN, download it from here: (Please don't link to third party software) Any feedback would be appreciated for the benefit of everyone here.

Modified by user633449

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I'm gone to chrome,but I'll give it a try.

Modified by Seasick12

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You can find it by searching in google and also available in cnet and softpedia. It's developed by Rizonesoft. I personally downloaded it from the main website. Please let me know if you have problems.

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Give it a try and I'm very sure you'll be happy. I quite depend on multiple tabs and bookmarks and at this moment I've 15 open tabs including a youtube page and my process monitor is indicating a memory usage range between 3,000 K and 17,000 K not greater than 650 MB. CPU usage between 02 to 08. Also my FF used to stop responding regularly which reflected on my other applications and slowed their process. Since I installed FIREMIN my FF started working very quick. No more (NOT RESPONDING)

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Have you tried disabling plugins and addons?

You have a ****load of them and they will cause some serious problems if they dont work properly

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I disabled 1 add-on for graphics and I never used it anyway and AVG Safe Search which was disable automatically because it's not compatible with FF12. I completely agree with you that plugins and add-ons slow FF performance. The major thing here is that FIREMIN regulates FF memory usage and keeps it locked in a limited range which stops the memory leaking. My advise is you leave all plugins and add-ons then install it. After that you can decide if it's required to disable them or no.

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bisha45, the link you provided is dead. Also, please don't give links to unknown third-party software from suspicious looking sites ;)

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Tylerdowner, I'm just trying to help. Anyway if you search it in google you'll find it in legitimate websites.

Modified by bisha45

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Hey Bisha,thanks for your help. I've downloaded firemin (found it at cnet dot com) and run it but not being technically savvy I've no clue what it's really doing :-) how fast should I set the optimisation??

Modified by Seasick12

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For anyone reporting slowness, please try starting Firefox in Diagnose Firefox issues using Troubleshoot Mode. If you don't have the issue while all of your add-ons, extensions, and themes are disabled, you can try adding them back in one by one until you find the culprit. You should look at the Extensions and Themes troubleshooting guide and the Troubleshoot issues with plugins like Flash or Java to fix common Firefox problems article as well.

You could also try Creating a new profile.

This thread was originally about a gfx card issue, but I think it's become a general troubleshooting thread.

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No matter what you do, the slowness stays. After trying different things suggested here, nothing works to solve it so next I used two PC's at work and wiped them clean, re-installed Windows7, installed FireFox 12 without any addons, still same exact SLOW on both HP and Dell computers, these are newer computers that are fast with 16GB memory. Running in safe mode, same problem SLOW Firefox 12. It's the connection that Firefox 12 makes so slow reading pages, it takes long delay times sending and receiving info on what ever webpage you are on. Firefox 11 does not have this problem. I've also tried different configuration settings in about:config in Firefox but found nothing so far that solves Firefox 12 slow problems.

Those who use dial-up may not noticed SLOW but if you're using high speed internet, the SLOW of Firefox 12 makes it like slow dial-up! Very frustrating!!! The only solution so GO BACK to Firefox 11 until they fix 12. I don't even understand why all these rapid Firefox updates! It almost like they are doing it just to have the highest version number than the other browsers!

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I agree a40098, as I've said before I'm not that tech savvy so can anyone tell me how to go back to FF 11 and I'll see if it improves my problem?? It's ok I managed to go back but it was just as bad if not worse, ho hum.

Modified by Seasick12

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I've reinstalled FF 12 and I've no idea why but it "seems" to be running faster :-) I wont get too excited yet though just in case.

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I thought so too after I re-installed FF 12 but then after using it a while it showed it's ugly very slowness again. When it gets so horribly slow reading simple webpages, it gets really frustrating. I've been reading tons of complaints all over the web and tech sites about the same slow for others with Firefox 12 and yet to find one solution to the problem, most just went back to previous version Firefox they were using.

To go back to Firefox 11, you just click on the Firefox 11 file you downloaded and it will install over the Firefox 12 and you're back to version 11.

Hope version 12 is working out for you so far!!

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Please consider the situation carefully before following advice to downgrade to Firefox 11. Firefox 11 is no longer supported or secure so you increase the risk to your personal data and system

There is some possibility that Firefox 12 may use slightly more memory than Firefox 11. Disabling plugins and add-ons that are not actively in use will in many cases more than compensate for any increased memory use.

A better option may be to try out the beta channel, you may find it has fixes and or improvements that you like. One improvement is it includes a method of creating a new profile with a few mouse clicks.

Another advantage is that you almost always have the option of downgrading to a secure and supported firefox version if anything goes wrong.

Also, please note if you have a specific problem with Firefox 12 being slow, then by all means read the information and comments in this thread, but you will get a better answer if you post your own question in your own thread with full details of the problem, follow the links and prompts from [/questions/new].

As a final point note if you turn on telemetry that generates data about speed, startup times, and hangs and the developers get to to see the anonymised data

Modified by John99

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Doesn't matter what you do, new profile, turn on/off hardware acceleration, changed to Firefox 11 and the problem is still there.

Massive memory leak, I'm not even watching videos, streaming or anything it's ridiculous.

Memory usage starts at around 150-220MB, then spikes up to around 600, and if I use flash it could easily be around 900MB.

There's something terribly wrong with Firefox, stop making it compatible all the way back to the Pentium 1.

If people are too stupid/lazy to upgrade then that's their fault, but those with decent computers shouldn't have to use the same version that causes an intense memory leak because it lags for everything, typing, watching videos, changing between tabs.

Whatever Mozilla has done is making just a simple day of browsing a chore.

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Why not start your own thread for your own problems, as you are reporting

  • "Massive memory leak, I'm not even watching videos, streaming or anything it's ridiculous. "
  • "Not only does it load pages very slowly, sometimes the page will stop for a good 45 seconds and stop loading, only to finish it much later. "

I am not too sure how unusual your apparent memory usage is, for instance you say not watching videos but then mention using Flash. We do not know anything about your OS or amount of memory, or where you are obtaining these figures. To start your own thread ask a question by following the links and prompts from /questions/new

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John99, I started this thread TWO weeks ago and 419 people have reported having the same problem and to date there has been no solution. Can you help?

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I will have a read through the thread again.

The problem with a general title like firefox is slow is that of the 400+ million users some of those will agree with the title as describing their situation, regardless of what OS equipment and other software is in use. There are many factors potentially affecting the comparative speed of firefox.

Yes I guess you have been ignored rather with all the other questions being asked.

You appear to have tried new profiles in Firefox, and also tried Google Chrome. Your OS is Vista so presumably IE is available also.

When you talk about Firefox lagging when two tabs are opening are you meaning ordinary pages such as looking at and typing on this forum page whilst waiting for a couple of pages open to display different threads from the forum.

Or are you doing things that may make Firefox work hard such as playing an interactive game whilst opening a tab to stream a High Definition video whilst another sorts through a large webmail archive.

What do you mean by a lag and how bad is it. Does a page take minutes to load or is just not quite as snappy as it was some other day.

Are both chrome and IE much faster in similar situations, and if so how much faster.(I am not suggesting you use firebug to check timings to the millisecond just give me some idea of how bad firefox is at present. ) Was Firefox good previously, if so when,and what version ?

Please give an example of some simple, and public web pages you have problems with, ones we can try, paste three web addresses from the locaton bar into your next reply.

Modified by John99

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