I know it's not answer, but this is a common problem on Macs too.
I found the 100% CPU usage was caused by a couple different Firefox add-ons that I was running. Namely Ghostery and one other that I don't remember the name of right now.
My suggestion is to uninstall your add-ons, then if the problem is gone, add them back one at a time. Each time you add one, close Firefox and see if it's still hogging your CPU, if it is, uninstall it and move on to the next one.
...start with the addons. I'm only assuming that the op wasn't running anything else. I've had a problem like this and it did turn out to be an addon. Other than that I've never had any problems with Firefox. It's still a great browser for me. You should also try to add more memory. Make sure your system is clean, no viruses, spyware, etc..
For anybody that's mentioned asking a question of Firefox support and never received a response, go there and look at how many questions come in a day. This has happened to me before. I asked a question which was never answered. It was frustrating. The way I understand it though, because FF is free and open source, the people that answer those questions are volunteers. There's only so many people to answer questions. If I'm wrong I'm sure someone will correct me. You'd probably get an answer faster on a forum. Also search, google search, forum search, firefox support search. Sometimes that's why questions don't get answered. They've already been asked.
I have used Firefox and other browsers for years. But I found that Firefox uses more than Opera, Chrome, IE, and some smaller browsers. It got to the point that I just quit using Firefox at all. The reason for that is firefox uses more CPU's than you would think. I also tried to get help from Mozilla and also got no response. It seems that Mozilla just doesn't care about their users for Firefox. txcounselor62
I agree, it is a hog. It seems to have a lot of issues with memory leaks especially when using flashplayer or pages that have a lot of flash ads. Some of the addons seem to make it worse, namely flashblock and adblock as well as avg safesearch to some degree. Mine does run better with the adblock disable, but still crashes at times.
I love Firefox and like to use it over IE, but today I checked my CPU usage when using Firefox and it was 53 - 68%, and this was after I followed the tips and advice offered here. (Storing history for 30 days, clearing history, etc.) When I switched to I.E., my CPU usage is down to 3% with a high of 15%. Is there anything else we can do? Thanks!
I agree usage is beyond a joke, have been using Firefox since its inception but lately every update seems to cause more hassles. Absolutely no response from support to address problems I asked about after latest two updates so I have discontinued using what used to be a very good product. I have not used IE for over 12 years and had been happy always to promote F-fox but NOT ANY MORE. I'm an Opera fan now.
I have found that, especially with windows 7, that fire fox and IE use up alot of my processor and memory. Once i started using GOOGLE CHROME i haven't had that problem. I have noticed that CHROME is a better browser and all the annoying tool bars that try and download on to my PC will not load or even work with CHROME. so that is alot of memory that i am not using. It is definitely worth looking into. Here is a link to download GOOGLE CHROME.
It seems that almost every browser is listed hare as a hog, I have add Chrome to the list. It's not bad if you have one or 2 tabs open but I work with 6 or 7 and at times more. At that point my PC just goes on vacation for what seems minutes at a time. Killing a few tabs does the trick. I get better performance using several browsers (opera, chrome, ff and ie) rather than have more than 5 chrome tabs open.
The Scottrader Elite program works with your default browser and was apparantly designed for IE. When I installed Chrome and made it the default browser, it made Scottrader Elite run like molassas in the dead of winter. I didn't figure this out until I tried to sell stock and the order wouldn't go through. Switched back to I.E. and the problem went away. This was when Chrome first came out and the problem may have been resolved. However, from an investor standpoint, the last thing you want to worry about is whether or not your buy/sell orders are going to go through.
Maybe getting a new pc would help, but my current setup just can't run Firefox like it used to. It uses up all my system resources. I don't know why---- It never did that before. But now it always slows me up and then it requires that I "end the process". It's really too bad because Firefox ued to be so much fun.
I am running OSX.6.3 on my iMac and when trying to edit Videos got the message that i did not have enough harddisk space to load the film. I checked the cache and found that Firefox had overloaded it with everything I had visited on the Web and had not been cleared when I had run a cache cleaner. I then decided to remove Firefox and everything affiliated with it and voila 239 Gb of free space! Unbelievable, i only had 19 Gigs free before the cleanup! I'm sorry to lose Firefox but will have to use Safari which is part of the Mac system but doesn't quite match Firefox but at least my machine can breath again!
It is bouncing between 3 and 24% of my CPU. I think you are talking about your RAM usage. I use CachemanXP to monitor my cpu and ram usage. It takes a few hours of moderate to heavy surfing to eat up a good chunk of my 2gb of ram and I usually restart FireFox when it gets down to about 500mb left of ram.
About this computer? I've been threatening to format it for 2 years now but I keep fixing the problems. Socket 478 3ghz P4 HT single core with pc5300 ram, 2gb. Not a blazer at all and runs fine, click and go on cable.
My basic startup is 11 tabs I run at all times and open others for added info and searches. I usually start off with 6 other programs running and 43 processes on task manager. I still run smooth.
You may try getting and using Glary Utilities and run it, see what you can clean up.
Found this on the net,worth trying: http://www.dennisyang.com/archive/2007/08/15/firefox-memory-hog-solved/
Also,see this page: http://www.solo-technology.com/blog/2005/12/23/quick-firefox-tweak-free-mem/