I don't have a specific answer for the problem you have outlined, but please see the article Firefox consumes a lot of CPU resources, particularly the following sections:

• Extensions
• Windows Compatibility mode
• Windows prefetch .

Thanks for the reply...I changed the Windows Compatibility setting and it seems to have made some difference. I am going to see how Firefox works like this for a while before attempting to do anything else. It is a shame there are all these kinds of issues with this version.

Actually, I am just recently having this problem repeatedly with Firefox 3.6, which I have been using in it's many updates on Windows XP. It has become very frustrating and I am thinking of jumping to Chrome, which has recently been very well-reviewed - and I am a long time Firefox loyalist. I checked the solutions mentioned re: consuming CPU resources, but these do not seem to be the issue.

I just upgraded to FF 4 from 3.6, running Windows 7 on an HP TouchSmart tm2. With this upgrade FF responds to one click from the touch pad and then nothing, no response to any other selections. I have to use task manager to close it. I upgraded to FF 4 on a Macbook Pro and haven't had this problem.

On Apple Snow Leopard: I have this problem, too, and it is getting worse. Especially when I first start the computer up or when I don't coontinually use it. I am not a computer expert and don't want to mess around with the workings, but I sure hope Firefox fixes this soon!

Using FF4 during two weeks now ... I never arrived to close it properly, always by killing the process and I don't have installed any add-ons, tried with and without flash and other runtimes and less than 10 tabs ! Constantly freezing ... responding ... not responding (sometimes every 30 secs) ... can't switch between tabs anymore ... clicking on a link does nothing ... pouf firefox is crashing ... or eating all available memory and CPU and OS become so slow until I kill FF4. It append to me on Windows XP (4Gb), Mac OSX 10.6.7 (8Gb), ... It is strange to write that IE and others browsers are now more stable :)

I run off a MacBook and also have to use Hughesnet as my provider. I've had problems with Hughesnet freezing up, so at first I thought it was a problem there. I would go through the silly reboot stuff and find that my Firefox 4 was still frozen. I then go to Safari (which is slow, so that's why I prefer to use Firefox) and find things are working fine there. After a while, Firefox comes back to life and I switch back to using it. ANOTHER problem with version 4, my yahoo apps disappear from time to time. This IS a problem since I have so many of my sites in my book and no access to them when it disappears. I thought it was a yahoo problem, but it isn't, it has to do with Firefox version 4. It appears that version 4 has a lot of kinks that need to be ironed out, but these are the two main ones that I'm finding I have a problem with. I sure hope they get it fixed. I sure don't want to go to Safari (for one, I can't put up the yahoo toolbar on Safari).

My wife runs Firefox 4 on Windows XP with an AMD single core 3.2 GHz CPU and 2GB of RAM. I run Firefox 4 on Windows 7 with an AMD 1090T hexcore 3.2 GHz CPU and 8GB of RAM. On both systems, running with or without Add-ons, in or out of Safe Mode, and not in Windows Compatibility Mode, we are both constantly (every few minutes) harassed by "Mozilla Firefox (Not Responding)." These incidents last from 10 to 40 seconds and occur in triplets (three consecutive occurrences) before we are able to actually use the browser--until this annoyance is repeated within approximately 10-15 minutes.

In addition, the amount of RAM consumed by Firefox and its plugin-containers is almost 1/3 (33%) on each system. CPU use runs at 100% for 10-15 minutes on the Win XP system. I allocate one core to Firefox and one core to all the plugin-containers on the Win 7 system. Each of them also will run up to 100% for several minutes per occurrence.

Very annoyingly, keystrokes are often either dropped, scrambled, or both.

All of this began in Mozilla Firefox version 3.6.4 when the plugin-containers were introduced (a very poor method of protecting the Firefox kernel and maintaining stability). Since I am an application developer, I feel comfortable in saying from professional experience that these are the most poorly written code of any browser in use, today. Worse, they are destroying loyalty among longtime users! My family has been using Firefox since--as I recall--version 0.07 and is having great difficulty finding good reason to continue using Firefox. It seems that Firefox has just become too encumbered with crapware.

How did Firefox get such good reviews for the upgrade? Before I get "not responding" I get freeze up. I can't move the window for almost a minute; sometimes longer. How can Firefox survive with this kind of performance?

I switched to Chrome for awhile and came back after the upgrade; but I am seriously considering going back to Chrome. Certainly if this keeps up I will. It simply bogs my workflow down too much.

Surely Firefox is on this because it has to be a deal breaker for most users.

I'm running with Win7, on a 64bit dual core system. It that's not enough in the way of resources what it?

Frankly I was glad to read your note James, now I know this is truly a serious issue that is not going to be addressed by users helpful suggestions. So I can leave it and move on; and decide if I want to continue with my favorite browser of bail and jump on the Chrome bandwagon.

But surely this issue is on the top of Mozilla's fix list; they won't survive if this continues because even it's most loyal users, and I count myself among them, will simply abandon ship. The competition is steep and worthy.

This is good for Chrome, and even IE.

Screw all the noise. FF$ is a piece of crap! I can't do the simplest browser functions at all. Fix it or fuck it and roll back to 3.6. MS menaltlty is seriously in vogue here. This shit a a piece of crap beta.

$= FF version 4.0

mikecox: "How did Firefox get such good reviews for the upgrade?"

If you pay people enough they'll say anything.

why does the new version 4.0 not respond to keystrokes, clicking on links, constantly hangs up?

Its developed a personality disorder

oddbodd I don't buy that argument, it's cynical and conspiratorial.

Call me naive but PCMag, PCAdviser, CNet, NYtimes, etc would soon loose credibility if it were discovered; and it would be discovered, that they were being paid to write good reviews.

This update is really dreadful.

NOTHING has improved they have just made it less user friendly. We cannot organise bookmarks. We get tabs when we dont want them. Opening new pages is much slower. What a total waste of time.

Search for:

places.sqlite (history stuff+favicons etc etc)

urlclassifier3.sqlite (google phishing url's, will be rebuild)

Must be somewhere in your profile directory...DELETE them.

This is also happening to me,really poor,,why does mozilla keep changing firefox for the worse,@martijin2011,thanks but didnt work for me.

I think this started to happen after the very last 3x version and has been carried forward to 4x,but seems worse.

Tried making a new profile but still happens,im on chrome now which is actually faster than firefox on searching,and just seems to work great,and dare i say it IE isnt to bad.

My laptop is more than happy to run it i7,so i know its not the setup,,bye bye firfox,this will take ages to sort out,as they just will not listen and go about there daily business just trying to out do rival browsers

@Jdubnicka Hi, I am having these EXACT same issues.. maybe I ask please what change you made to Windows Compatibility setting? Thanks in advance... soo WISH I didn't upgrade to 4! uuuge! :(