Firefox has become very very slow




8 years ago
6 years ago


(Reporter: qawasa, Unassigned)


3.6 Branch
Windows 7

Firefox Tracking Flags

(Not tracked)


(Whiteboard: [closeme 2011-06-19])



8 years ago
User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 6.1; it; rv: Gecko/20100625 Firefox/3.6.6
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 6.1; it; rv: Gecko/20100625 Firefox/3.6.6

I used Firefox for many years with no problems. Since I installed version 3.6.6 italian, surfing on the web is very slow. I use also MS Explorer, and it is 5 times faster. Can you help me?


Reproducible: Always

Actual Results:  
The proble is always there

Expected Results:  
Probably there is a corrupted component or a wrong parameter (I use always default values)
Please, try safe mode it's indeed possible an add-on is slowing you down, safe mdoe temporarily disables them.
If the issue is in the profile, creating a new profile and importing old data into it could also help a lot (

Finally check that you security software (antivirus/firewall) are correctly handling the new version, the executable vhanges at each version and has to be re-allowed in those software usually.


8 years ago
Version: unspecified → 3.6 Branch
qawasa, please post your results
Whiteboard: [closeme 2011-06-19]
Please update to Firefox 7 and file a new bug if the problem still occurs.
Last Resolved: 7 years ago
Resolution: --- → INCOMPLETE

Comment 4

7 years ago
I am using ff 7 and ff 7 is VERY SLOW compared to some previous versions like 3.
I used to blaze through things.  I have a Pentium 4 HT 2.8GHz 3GB RAM with XP Pro SP3.  
it takes about: 
1-2 full seconds to click on a tab.
5 full seconds minimum to start
1 full second to render a very plain local html file
Jim, see comment 1 and 3. If safe mode helps, another possibility source of problem is direct2d/graphics driver issue.

Comment 6

7 years ago
this is the only app that is slow.

Comment 7

7 years ago
besides IE.  it was always a real slug.

Comment 8

7 years ago
did firefox --safe-mode and started up safe mode.
- switching between tabs is now practically instantaneous.  it's not like this otherwise.
- refreshing a local html file is instantaneous.  didn't used to be. (maybe I had firebug running at the time?)
- 5 seconds to restore tabs (most of that is internet communications probably, but most of this should be in the cache, shouldn't it?  unless the cache was invalidated through headers)

just installed machine fresh 5 months ago, so should not be a graphics driver problem.

Comment 9

7 years ago
this is quite possibly due to a plugin.  that stinks.  I shouldn't have to disable my plugins to get render speed.

Comment 10

7 years ago
- downloadthemall 2.0.8
- firebug 1.8.3
- fireshot 0.93
- mcafee scriptscan for firefox 14.4.1
- mcafee siteadvisor 3.4.0
- microsoft .net framework assistant 0.0.0
- places maintenance 1.0
- rainbow 1.4
- numerous java consoles which are not compatible with firefox. tsk tsk oracle...

Comment 11

7 years ago
narrowed it down. it's caused by mcafee siteadvisor 3.4.0

Comment 12

7 years ago
since making those changes and upgrading to firefox 9.0.1, firefox is now slow as molasses most of the time.  I am running Java 7.1.
I have 63 tabs (this is normal for me) and it isn't too bad right now. windows has just loaded up.  I have no idea why it's not consistent today.

it has crashed numerous times.

Comment 13

6 years ago
I am having problems again. it seems to happen because I have about 40-60 tabs AND because ff is 32-bit AND I am on a 32-bit system AND ff consumes (supposedly) 1.7GB peak according to the task manager. took about 15 minutes, but ff finally closed when I clicked the close button.

I wish there were a 64-bit version of ff, so when I get my 64-bit box, I will have something nice to transition to. 32-bit code has been around since the 386 in 1985. that's 28 years.  maybe it's time for a change...
I know 32-bit boxes still exist, so providing both 32-bit and 64-bit executables would be a good thing.

I will try safe mode. I did not see these comments, or I would have tried them. I did not get the email. sorry guys...

as I start up ff with all those tabs in --safe-mode,it consumes 144216KB... and climbing. yahoo mail is running in one tab if this makes any difference. but I discovered that no matter what I do, firefox just leaks memory.
before closing ff, I have been right clicking on links and opening that in a new tab... and if it wasn't what I wanted, I closed the tab. lonbg list of about 90 links, and I didn't finish it.
click show all. (their search engine is broken)
it's been 10 minutes and its memory usage is now 237804K. I haven't done anything.
at this rate, I had better work fast. please eliminate this 

I think it's reaching its memory limit, and after this it can't allocate any more memory and who knows what happens. but at that point, ff becomes a dead horse practically. it will respond to a click after 10-20 minutes, and it won't redraw the window during that time.

I just got finished deleting the places database as per another request in a different bug report.

now it only becomess low if I have a lot of tabs open for a long time.  so the bug characteristics have changed, but still there. it's due to a memory leak. right now it leaks at a rate of (well, it seems to have stopped now). hmm. as I close a tab,memory has jumped up 100MB. as I type characters at
I notice that memory is leaking at a regular rate.

this is not good. it's at 346408K now. I closed another tab,and the peak mem usage is now 405548K and VM size is currently 321412K. make that 321788K. it's leaking. again,slowly. it seems like the tab management has a LOT of bugs in ff 17.0.1. if you want me to test a nightly, I can.
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