In testing out Firefox 3 RC1 I realized that when loading up a page in a foreground tab when two or more tabs were present, my single core CPU maxed out and loading slowed to a crawl making the browser unresponsive until I switched the tab into the background to let it finish loading. At that point, CPU usage returned to normal. As long as the tab that was loading remained in the background, the CPU never rose above an average of 20% max not counting the occasional spike or two from flash and script content.
Other folks were having these problems also which included high initial memory use for some as well so after much troubleshooting and constructive cursing I finally found the culprit that was causing this high CPU/memory use problem and I’m passing it on.
The fix is actually pretty simple and involves changing the state of “browser.cache.memory.enable” in Firefox’s “about:config“. Just follow the simple instructions under the image below:
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Type “about:config” into the FIrefox 3 RC1 location bar and tell it you’ll be careful (you’ll see what I mean).
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When the list of configuration options shows up, type “cache” without the quotes into the search bar as shown above. A list of all entries will appear with the word “cache” in them.
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Change the state of the “browser.cache.memory.enable” entry to “false” by double clicking on the entry itself. Make sure the state has indeed changed to “false”.
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Restart the browser and you’re done.
Firefox RC1 should now run right along nice and fast no matter what tab is loading in the foreground and without the high CPU use as I saw before the change and apparently the memory problem is also fixed. Performance in RC1 does not seem to be degraded at all by this change and speeds things up nicely.
If this fix helps anyone running Firefox RC1, please leave a comment and let me know as I’m really curious if this works for others as well.
It fixed my Firefox RC1 100% cpu usage.
Thanks for the help
@Greg:
Glad I could help and BTW, I’m seeing the same problem in RC2 (I knew where to scarf the latest build of RC2 off of Mozilla’s FTP server, mwua-ha-ha-ha!). The same fix works for that build also. Thanks for commenting!
I’ll have to update the post with the links to the forum thread I started and the bug report I filed. Can’t believe I didn’t do that in the first place. Must be gettin’ old or something.
I upgraded from FF 2 to FF 3 and was immediately faced with FF running very slow and CPU maxed. Your fix has speed things up dramatically. The CPU still spikes to max, but only for a fleeting moment. Before it was staying there like 5 to 10 secs!
Marcus, (welcome!)
Glad it worked out for you. This seems to be working for a lot of folks out there which tells me the problem is indeed wide spread. I have 2 links on the updated post mentioned at the beginning of this post. One links to the Mozillazine forum thread on this and the second the the bug report I filed. Could you possibly leave this info and your system info on one of them? It would help immensely.
My problem looked similar but turned out to be caused be a bug with LiveBookMarks loading:
https://bugzilla.mozilla.org/show_bug.cgi?id=329534
Bug 329534 – Live bookmarks load way too aggressive (lock up/hang/freeze browser)
Still open from 2006-03-06 :
SilverWave, (welcome!)
I believe this problem is fixed in Firefox 3.01 which is due early to mid July. It’s a stability release and fixes a ton of problems that have been found since the release of 3.0.
I have noticed that the cpu and memory increase
). When I look at the process running it is firefox. It seems that every time I have firefox open and minimized (or am not using firefox and it is still loaded or idle for a few minutes), it becomes very active and consumes cpu and memory. The last time this happend I did a google search, had the list of results minimized, the page and was reading a txt file, then the HDD and memory consumption spiked.
when I minimize my tabs and do other non-resource intensive (read pdf, have txt file open ect..) all of a sudden I hear my hard drive crunching constantly as if I were doing a search or defraging (win xp, working on switching to linux
I have noticed this in both firefox 2 and the current 3 RC1 which I am using now.
I used this fix back when I had version 2 and it seemed to help.
Thanx Cipherheus
Hi Cipherheus,
Here’s a couple of suggestions that I’m sure will help.
First and foremost, the problem with your HDD crunching away like that is most likely due to Firefox populating the anti-phishing SQLite database (urlclassifier3.sqlite) with updated information and in Firefox 3 RC1 there’s a major bug with that along with several others. I strongly suggest updating to the final version of Firefox 3.0 asap. That should cure your problem.
On the off chance the problem still exists then you may have a corrupted profile. In this case it’s best to jot down a list of your extensions, backup your Bookmarks and uninstall Firefox completely. Once that’s done do a fresh install of Firefox, import (restore) your bookmarks and install your extensions.
By the way, Firefox does not give up any memory when it’s minimized as other programs do so you’ll definitely get some benefit from this Firefox tweak post I’ve written up on my other site. I use this tweak myself and it works great.
Hope this helps.
It worked very fine for me too. Thanks from Brazil.
JoseF
You’re welcome, from Vermont.
Thanks a lot mate, the tweak does look like its working. CPU now is 00 rather than 99% when firefox is idle. Me from Malaysia.
Zack,
Glad it worked to you. Interesting it’s working for so many Firefox 3 users.
Hey thanks very much for this tip, what puzzles me is that while you talk about RC1 solution appears to work as well for the present/latest release.
All the same, your post solved my problems on the spot! Cheers!
KM,
(welcome)
Indeed it does work on the final release and I have an updated post that’s located on a new site just for that reason. You can find the updated article by clicking the link at the top of this page.
Glad it worked for you.
thanks a million this advice got me going again
Thanks a lot, it look like its working cpu usage went down
I tried this fix on my FF ver 3, but everytime I go into Gametrailers.com to watch the game video’s I still get 100% cpu usage. I thought at first my 20mb was slow but I checked that and was getting 17mb at the time.
you can’t imagine how i hoped it would have worked for me. everytime i try to run youtube videos it goes to 100% and stays. even when i close the tab it still stays at 100%.
any more suggestions would be greatly accepted.
ray
Hi ray,
This fix was only for those experiencing high CPU usage when loading/reloading a tab in the foreground in a multi-tab situation. The problem only affects some and not others. The Flash problem relates to the poor quality of Adobe’s Flash plugin for Firefox/Opera and not really a function or problem with Firefox.
I’m finding in my troubleshooting that a combination of CPU and certain video cards/drivers will increase or decrease the severity of the problem but I haven’t narrowed it down to specific combination(s) yet. I can tell you that running “on-board” video or a poor quality video card can make the problem significantly worse (these two types tend to use the CPU to power some or all of the video on your PC thereby increasing the problem).
I was able to fix my problem with the following instructions from the Roboform website. Believe me before this I had done everything I could find. Most likely I have a more efficient computer now but I also have a working FireFox using the latest Flash upgrade. I hope this helps some others that just could find a solution.
Reinstall Firefox if Browser Profile is Damaged.
Due to a number of reasons your browser profile may become damaged and corrupted.
Symptoms: old RF adapter cannot be uninstalled, skins are corrupted, etc.
The only way to fix a problem is to do a complete reinstall of Firefox and Mozilla:
* Close all Firefox and Mozilla windows and its taskbar icon.
* Uninstall Firefox from “Control Panel -> Add/Remove Programs”.
* Uninstall Mozilla from “Control Panel -> Add/Remove Programs”.
* Delete folder C:\Documents and Settings\\Application Data\Mozilla.
* Delete folder C:\Program Files\Mozilla Firefox.
* Delete folder C:\Program Files\mozilla.org.
* Delete folder C:\Program Files\Common Files\mozilla.org.
* Search for all folders that contain “Firefox” or “Mozilla” in their name and delete them.
* Install Firefox (or Mozilla) again.
* Install RoboForm Adapter/Extension as described above.
Similar instructions apply to Netscape.
My version 3.0.1 and I had the same problem. Thanks for publishing the fix it works perfectly now.
Regards from Budapest, Hungary
Worked great…thanks man…
Great fix
I just downloaded Firefox 3.0.3 the other day and this problem started. Your fix worked.
Here’s a tip for another problem in Firefox that works:
For those of you out there using one of the real browsers (among others, I am pointing at Firefox), you might find that version 3 of Firefox, while being a brilliant browser for the rest, built-in virusscan on completed downloads is a bit annoying. In my case, it always freezes for about two seconds while initiating the scan. Plus, having a good virusscanner already active, I don’t really see the point.
You can disable this feature by typing about:config in the address bar, and then filtering on browser.download.manager.scanWhenDone. Double click this line to set the value to false.
Problem solved.
I just downloaded Firefox 3.0.3 the other day and this problem started. Your fix worked.
Here’s a tip for another problem in Firefox that works:
from
http://fluppe.wordpress.com/2008/08/05/firefox-disabling-automatic-virus-scan-on-downloaded-files/
Firefox 3: Disabling Automatic Virus Scan on Completed Downloads
For those of you out there using one of the real browsers (among others, I am pointing at Firefox), you might find that version 3 of Firefox, while being a brilliant browser for the rest, built-in virusscan on completed downloads is a bit annoying. In my case, it always freezes for about two seconds while initiating the scan. Plus, having a good virusscanner already active, I don’t really see the point.
You can disable this feature by typing about:config in the address bar, and then filtering on browser.download.manager.scanWhenDone. Double click this line to set the value to false.
Problem solved.
Man you guys rock…. I have 3.0.3 and it’s been killing me trying to do anything. This fix worked perfect and fixed everything.
Thanks again
Awesome fix. Was struggling with FF 3.0.4 and even before.
Thanks heaps
Great tweak. Its working. From CPU usage of 75% it has consistently came down to below 20 % while downloading in tabs. Thanks from INDIA
Hurray! It worked, it worked, it worked!!!!
Thanks man!
Hey Teo,
You’re very welcome.
By the way, Firefox 3.1 fixes the problem you and others experienced so when 3.1 hits the streets you might want to back up all your bookmarks and extensions and start from scratch instead of upgrading at that point since you don’t need the “fix” at that point. Besides, it’s always good to start fresh once in awhile (it’s easily done, I do it on a regular basis while testing) and 3.1 is the perfect chance.
Hi Kirk M,
thanks very much for publishing this fix works like a treat!
Gabi
This is awesome! Thanks a bunch!
Happy Holidays,
Tracy
Same to you Tracy and glad the fix worked. You can change the “fix” back to “True” when Firefox 3.1 comes out.
Thanks a lot !
Happy Holidays !
You are a blessing! It was horrible surfing with FF3.0.4 at 100% CPU. Your fixed knocked it down to under 10% max after loading page.
well i am using a 1.8ghz P4 cpu with 256 mb ddr ram. Well i tried this tweak on my firefox 2.0.02. well it did nt show much of change.Any i still appreciate your blog!
@venkateshhh,
The “fix” I wrote about only applies to Firefox 3.0.*, not Firefox 2. Considering that your version of Firefox is considered no longer secure (and full of bugs that have been long fixed) I highly recommend that you update to the latest version. Back up your bookmarks first of course and check your extensions against the Firefox Add-ons site beforehand to make sure which ones might not be compatible with the latest version of Firefox (shouldn’t be more than a few if any). Whether you’ll need the fix or not with Firefox 3, it’s still a much better browser by far than Firefox 2 ever was.
Not too sure what kind of trick this is, but it seem it has solved a problem i had since first upgrading to FF 3 .
Great tip, Thanks so much Kirk M.
For me WinXP need a lot of resoueces,so if the proceccesor is not good enough to handle WinXP it hangs on every application.I try a lot of fixes to resolve my poor Intel Celeron 331MHZ issues for especially Windows Explorer (not IE) and up to date i got poor CPU improvements.
Mig,
You didn’t happen to mention how much memory you’re running but I imagine it’s way below minimum requirements although I have run XP on this type of processor before. XP requires 128 Mb’s of ram minimum just to run the OS never mind any programs. 256 Mb’s is absolute minimum in order to run XP correctly and you’ll still be very limited as to what you can do beyond the basics. At the very least you need to max out the memory in your PC.
I’m afraid it’s way past time to upgrade my friend. And there are still fantastic deals to be had for refurbished PC’s that are loaded with XP.
This is AWESOME! Thank you very much. Firefox was tankin out my system suddenly. I thought it might be spamware or a virus or something. I uninstalled and reinstalled. It didn’t do anything.
You’re brilliant!
My computer stalled when browsing with FF (CPU usage 100%). Clicking anywhere on the screen made continue. I visited dozens of sites. They all talked about viruses and trojan horses. One site even mentioned reformatting!! Only your site came with the right solution: tweaking FF itself.
Thank you very much. Your site is already in my Favorites.
u are awesome dude…. firefox should honestly hire you …
how u found this solution is beyond me.. and i am a computer science graduate and work in programming….
Can you tell me what you mean by the ‘location bar’ ? I am really sick and tired of the cpu usage going up to 100%.
Ok, I got it, and I’ve changed the state to false. Will let you know how it goes. Sincerely hope it works.
This fix along with disabling the “Java Quick Starter” plugin really worked!
Partha – Glad it worked for you. I’ll have to try disabling the Java Quick Starter plugin myself and see what happens. Thanks for mentioning it.
Where do I find the java quick start plugin to disable it?
Jen (welcome!),
Depending on your version of Java, you will find the Java Quick Start plugin in the “Extensions” tab in the “Add ons” dialog box (you’ll find it under the “Tools” menu). not the “Plugins” tab like you might think. You can disabled it from there. You’ll have to restart the browser once you do though for it to take affect.
Hi
I tried it on my Firefox 3.0.7 and
it did not work, this firefox is running on linux CentOS4.7.
When i am running Pandora.com and listening to music the cpu usage goes to 93 and makes all navigation impossible …
I also checks my news papper and i think java have to do with it but i do not have java quick starter in my firefox, so i am looking for some way to fix the problem …
Matte
I tried this procedure on Firefox 2.0 with great results. Now I don’t have to wait (and wait) for a response from my system when Firefox is consuming CPU time.
Note: CPU utilization still reaches 100% now and then, but the system does not stall other programs when Firefox is processing its webpage. (I am running Windows Server 2003).
This solution solved the problem partially.
I have the Java quick starter plugin turned off along with your above given solution, but as soon as I load a foreground tab the CPU usage shoots to 100% then starts fluctuating from 20% – 100%.
I have given up on this problem altogether. If I have anything else open and enlarged, in addition to firefox, it seems to go to very high cpu and stops. So I have taken to closing firefox via task manager when this happens, and then restarting, and minimising all other screens if I’m not working on them.
Wow, I think that fixed my problem. THANKS!
I had this same issue with Firefox 2.
I have 3 now and after disabling the Cache and turning off the Java it still runs like crazy also uses over 200Meg of Ram.
I also shut down the .net Framework…
Really dumbing down my system…
Any other Fixes?
I fixed this by using chrome
I have a quad core 9550 with 8 MB of ram and firefox uses 100 percent on all cores. I used to love firefox but i dont know whats going on. IE explorer and safari do the exact same thing. I have switched to crome and no more CPU hogs on my system. I miss my firefox
When I try this on my system running Firefox 3.0.14, it does something quite interesting:
When I open a bookmark, instead of it opening in the regular way, a sidebar type window opens on the left and loads the link there! There is no tab in the “regular” window and no tabs are opened.
I double checked to make certain I had changed the correct boolean in firefox, and I did, so now I am curious why this happens!!
Help. I cannot use Firefox on my single core system (AMD 2 GHz AthlonXP)
Larry
After sending my previous message, I returned to Firefox (I am using Safari for Windows right now – I really like that also, but, Firefox allows me to add so much to it, and, its basic operation is so good, I can’t find anything else even close to it!). I re-loaded it, closed any open tabs which were retained from previous use, and tried the bookmarked link again. This time it did NOT do the same thing (open in a sidebar rather than in a tab). It seems to work well now…
It looks as though Firefox is now much faster, subjectively, than it was before editing the boolean value as shown here. It still looks as though it will “eat” a lot of memory but it doesn’t freeze when surfing, at least not yet. I will test more and post here if I learn anything.
I am going to have to learn more about the boolean flags and such in firefox so I can work on some other issues! I don’t know where to start but I usually just google an appropriate phrase and start looking at the resulting web pages.
OFF TOPIC RAVING: The internet is so rich in very high tech information (some of which is even true!), I haven’t opened any of my technical books and other sources for years. I recall having a tremendous problem in the past, in my companies, just keeping track of all the books and magazines and other references I had stored in huge book-cases, so I could look up some technology or component or software information and so on. I even had to hire someone to do it for me as it was consuming too much of my time. Now, the internet does that for me….. amazing! (I am an electrical engineer, MSEE-type, and I am not that easily impressed after 40+ years of experience, so my amazement at the vastness of the internet and the amount of information it places at my finger-tips is real and sincere. What I could have done forty years ago if I’d had the internet, when I was young ! ! ! Heck, what I am doing now even though I am about worn out!!!)
Sorry for going off-topic, but the internet deserves the praise….
Larry
After Doing this, Firefox can Barely Load a website.
awsome tip!!!
i have been strugling with my old hp celeron laptop and i did noticed that any other browser will not use that much of a memory and cpu as firefox does, but i was missing all the addond of firefox, so i had to get back to firefox with 100cpu and bearly moving pc… this all was till i read this tip. awsome!!! now iahve 30 tabs open with cpu at 7% and memory 152 (used by firefox)
thanks.
all the best.
Turning Java off solved my CPU usage problem.
I have tried this fix and it worked perfectly.
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It seems to work for me… Thank you!
From Hungary!
This fix made a big improvement for me running Firefox/3.6.2
Worked perfectly – great great tip. So simple to do.
Greetings from Firefox 3.6.8 on a Mac G4 1.25GHz/Leopard. I use FF on a daily basis with Firebug for web design, and the 100% CPU usage was the single most frustrating and aggravating thing I’d ever encountered on my Mac, which otherwise gives me no problems at all.
After Googling “Firefox CPU 100%” and other similar search variations I came up with nothing until 10 minutes ago, when your solution popped up.
Amazingly with your fix (which took what, a couple of seconds to do?) my CPU usage has gone down to 30-40% at idle with FF on. There’s an occasional spike when processing new sites, which is expected, but it totally drops back down afterwards.
Dood. Thanks so much. You’re a total lifesaver. I’ll keep you posted on any developments.
Sweet, thanks for this! Especially since my laptop won’t take a GPU card.
Also I verified that your fix is a Mozilla acceptable fix (if anyone cares)
Dropped my RAM consumption noticeably. Stays around 150MB – 170MB with lots of windows open from flickr, high resolution photos. Before changing, memory use was going to the mid 200s often and sometimes over 300MB.
Firefox MozillaZine says “Setting this preference to false causes less memory to be used but also increases the load time of previously visited pages and dialogs, especially those of secure sites.”
No noticeable load time issue yet. I’m happy with the new setting. Previously I would be typing or something and it would do nothing and then the laptop would enter all my keystrokes in a burst. I’d look at memory and it was over 300MB for Firefox. Not anymore.
After trying it for a day I found the memory creeped up to just over 200MB after a while but not as bad as before so I still use the fix mentioned here and I have one more tweak to add to this.
Most of us have uninstalled many extensions that we tried. This leaves residual junk in the “about:config” mentioned above, even after extension uninstall.
Do this at your own risk, I take no responsibility, should be safe though, it is a method described in FireFox support pages. (link below)
So as an additional measure, first uninstall any extensions you really don’t need. Make note of your previous setting changes you made in FireFox Tools > Options, or in any of your exension’s options. You will need to reinstate them later because they will be reset to their defaults. Then close Firefox and go into your Firefox profile. If you don’t know how to find it, go to “Run…”, type in %appdata%, open Mozilla folder then Firefox folder then Profiles folder, now you see your profile with an odd name, open it. Find the “prefs.js” file, cut and paste it to the desktop. It can be moved back if you don’t like the result. Or you can just delete it from your desktop later. Restart FireFox. When you restart Firefox this file will be rebuilt. Only “about:config” entries for currently used extensions will be in it now. This idea is officially explained here by Firefox support:
http://kb.mozillazine.org/Resetting_preferences
You will need to reset your browser and extension options if you had those changed differently from their defaults.
Now my Firefox memory usage stays at half of that 300MB+ spot. I have 16 extensions installed and, for example with a dozen or more tabs open from a variety of web site types for an extended time, usage goes up to 175MB. Then when I close maybe 4 or five of those tabs, it drops immediately to 150MB memory use for Firefox. Very controlled and sensible. You still may need to be careful about which extensions you have, certain ones may be memory killers.
@Mike_tn – Glad the fix worked for you. Obviously certain hardware configurations cause memory problems with Firefox. Unfortunately, there are so many different hardware configs out there it’s impossible to track down exactly what’s causing the high memory use.
And many thanks for your “prefs.js” solution. I knew of this a long time ago and had since forgotten it. It always pays to keep your profile clean and tidy. The “Places Cleaner” add-on might also help a bit by fragmenting (optimizing) the Places database.
Thank you. That did help alot. But im still having a little problem with it. I play games on Facebook alot and especially Collapse really slows down after playing a couple games. Firefox will start out using about 43,964 memory and by the fourth game its using 138,054. Then the game crawls. But I do want to thank you for your honest help. Kudo’s to you.
Dorothy – Glad the fix helped some. Unfortunately it’s really hard to pin down a memory problem when playing a Flash based game such as Collapse (my wife plays that one as well). It boils down to too many variables such as, what specific OS are you using (Windows XP, Vista or Windows 7… Mac OSX, Linux), what version of Firefox are you running, what Firefox add-ons do you have installed, are your plugins (Flash, Java, etc) up to date with the latest version, How old is your computer and what are it’s basic specs…
That’s what I mean about being hard to pin down.
What Most folks don’t do is to clear their Firefox history and cache on a regular basis which leads to large amounts of history and cache data which, stored over a long period of time, can get corrupted and cause all sorts of weird problems. So clearing these two items regularly might help some. I know it’s not a specific fix but it’s a starting point anyway.
Thank you very much buddy!It has worked for me also. Love from Istanbul.
Got 1 Gb memory on an Archos 10 and, after chasing after pertinent info on Google, Bing or Yahoo, firefox was maxing me out. Kept going to the Clear Cache option in Tools – apparently it doesn’t work because, once applying your Cache Memory fix, I had my old firefox back! Fast page loading, no more hitting the refresh button to re-load incomplete pages, .jpg pages loading effortlessly, etc.
Using 3.6.1 which is the best of the 3.* series but still has speed and cpu and memory issues. So, thanks and thanks and thanks.
Thanks a heap man! This was superb! you solved a big big irritating problem of mine!
You’re a genius!
Has Mozilla employed you yet?
Outstanding! It really made the difference. I was ready to scrap FireFox altogether.
Thank you for your expert opinion!
It fixed my Firefox RC1 100% cpu usage.
Thanks for the help….
Hi
What’s up with firefox 7? 98% cpu used!
I was forced to upgrade to FF8 by one of my apps….then the guru told me to add ‘Firebug’….thought I had lost everything….took days of reading forums to figure out that even with quad-core and huge memory, Firebug eat up CPU! Took it off and working fine now.