100 % CPU usage makes Firefox unusable :-(

[andyfellwalker]

The problem went away when I increased my physical memory from 768MB to 1.5GB

I was upgrading anyway and wouldn't have chosen this solution to fix Firefox

[trajano]

From what I saw, it seems that if the preference file gets a bit excessive in size for a pref entry, Firefox starts manifesting the high thread CPU problem.

NoScript seems to be the culprit. Specifically the user_pref("capability.policy.maonoscript.sites", ...) line in the preference which gets excessively large as you use NoScript.

For the time being, I just periodically trim the list to contain only the ones I regularly visit. However, a better fix would have to be done by either the NoScript developer or Firefox.

For the NoScript dev, I think the list of sites should be moved out of the preference file and kept on its own database. Either a plain text file which generates a BDB file for memory efficiency (the BDB file contains the same data as the text file, but it is stored in a structure that can be searched very quickly, but the data does not remain in memory).

[malliz]

^ You could post that in the extensions thread if you like
http://forums.mozillazine.org/viewtopic.php?t=526234

[WeeDie]

I have similar issues. And I believe it started after installation of several extensions.

Sysinternals process explorer tells me firefox.exe!jpeg_fdct_islow +0x27ae9 is the cause of excessive CPU usage. Causing firefox to use up to around 70-80% of CPU load. On restart the problem disappears, but returns sooner or later on surfing, opening tabs, surfing around at no particular site, just in general surfing around the web. No way of telling what sites are causing it, because the problem kind of builds up.

I tried deactivating extensions to find the culprit.
And after deactivating Noscript 1.1.4.6 I thought I had found the faulting extension.

But I was wrong, the problem remains, only it builds up slower then before I think. And the load doesn't go above 30-40% now. But it is a resolute load. On restart of firefox the browser is mostly idle upon inactivity and will suffice with ~ 7% load every 5 second or so. Opening new pages will push it up to around 50% but then it goes in to idle mode again.
After a while however, something is adding up on the CPU load. I wish there was a simple way of tell what it is..


Running Firefox 2.0.0.2

Extensions installed:

* Add Bookmark Here 0.5.5
* Context Search 0.4.1
* DOM Inspector 1.8.1.2
* Firebug 1.01
* Flashblock 1.5.2
* Foxmarks Bookmark Synchronizer 0.89
* Google Toolbar for Firefox 3.0.20070217W
* IE Tab 1.3.1.20070126
* InfoLister 0.9f
* NoScript 1.1.4.6.070304 [disabled]
* PDF Download 0.7.9
* Scrollbar Anywhere 0.9.1
* Super DragAndGo 0.2.6
* Tab Mix Plus 0.3.5.2
* Talkback 2.0.0.2
* URL Link 2.00.3
* Web Developer 1.1.3
* Zend Studio Toolbar 2.0.0 [disabled]

[Giorgio Maone]

I don't know if it's been already mentioned, but my winner is definitely Firebug.
Just "soft" disable it (from its UI) for normal navigation and enable it only when needed.

BTW, if for those who are interested, NoScript 1.1.4.6.070417 contains many performance improvements, most notable dramatically reduced reloading times on permission change.

[WeeDie]

I have Firebug disabled. Not as an extension, but not running in debugmode. So I don't think that was the error, at least not for me.


However, I installed the following extensions, on top of the above mentioned.

FasterFox
Clearcache
and Live HTTP Headers

and after that I haven't run into the problem anymore.. no idea why or how, but the problem seems to be gone. At least, it have been for days of heavy surfing.

I would guess that FasterFox may have done something to fix it, sense I think it deals with some rendering tweaks.

I installed 2.0.0.3 today.

[VanillaMozilla]

It's good you got it fixed. FasterFox may possibly have undone some incorrect settings. But it may be capable of introducing problems too. Note that even if you uninstall FasterFox, the changes will remain. If you should need to undo the changes, the only ways to do that are to find them and change them manually (nondefault settings are bold on the about:config page) or to create a new profile.

And do note that Firefox works fine without FasterFox. It works on tens of millions of computers. I can't personally vouch for all of them, but I can vouch for several of them between Win 98SE with a dialup modem to a 3 GHz XP with a 100 MBPS connection. You don't need to feel that you need an extension to get acceptable performance.

[WeeDie]

Nah, I don't see any noticable difference in speed.
but I'm running it in performance mode within RFC specs, so it can hardly hurt anyone if I keep it.

I just wanted to mention it here, in case it manage to help someone else. If it does, maybe we could easier find out the cause of the problem, at least for many of us.

[TronicVolta]

I believe the 100% CPU is caused by Firefox's inability to handle swf files embedded using wmode="transparent."

[VanillaMozilla]

If I'm not mistaken, swf files are not handled by Firefox, except possibly to hand them off to a plugin.

[Deltoid]

I am experiencing 100% CPU problems with pages that have .swf (shockwave flash) files on them, and in researching the problem, found my way here. I originally posted my problem and the interim (unhappy) solution that I’ve found so far here: http://forums.mozillazine.org/viewtopic.php?t=516122

I’ve also tested with http://www.dillout.de/share/test.html -- as suggested in another thread on 100% CPU utilization. The results are that in Firefox, my CPU utilization is around 40%, with a 10% fluctuation up and down. Testing with IE, my CPU utilization is 2%. I’ll repeat that: With Firefox it’s 40% and with IE7 it’s only 2%.

My immediate concern is that when I go to a page that has several dozen .swf audio controls (not movies, no animation, just .swf audio players), then my CPU utilization goes to 100%, and my fairly robust notebook computer is tanked. I have a recent Dell Inspiron 9300 with 2GB RAM, an Nvidia GeForce Go 6800 card with 256MB, DirectX 9.0c, Windows XP multi-media edition SP2, the latest drivers and bios, no diagnostic problems and no virus or spyware detected. Also, I have no problems watching movies, listening to audio, or playing any multi-media content when not using Firefox.

The solution of blocking flash is fine for advertisements but not for the audio content that I need to listen to from the .swf controls on a language learning site that I subscribe to. And besides, I want the freedom to choose my content based on preference, not on an under-acknowledged browser bug. (Sorry … just had to get that out.)

I found that the unhappy solution is to go into Internet Options, accept the default security levels, then go to the Advanced tab and make sure that ActiveX is fully enabled. Then use IE. Since Firefox doesn’t use ActiveX, this has no effect on Firefox. So while IE works fine, Firefox is unable to handle the equivalent.

[Deltoid]

TronicVolta -

According to my research, you are correct that "transparent" is the least efficient.
So I experimented with:

param name="wmode" value="opaque"

This is supposed to be the most processor-friendly.
It may be slightly better, but it doesn’t solve the problem.

If you can think of any other settings, I’ll plug them in and try them.

[Deltoid]

Also just tested with:
value="window"
No real difference.

[VanillaMozilla]

The results are that in Firefox, my CPU utilization is around 40%, with a 10% fluctuation up and down. Testing with IE, my CPU utilization is 2%.

<b>That's because the Flash plugin for IE is a different program.</b> (See http://kb.mozillazine.org/Flash , especially the sections on installing in Windows, uninstalling, and troubleshooting.) Sorry, there's been a lot of trouble with Flash. You can try to update it, or complain to the Web site or the Flash people. But Flash is whats burning up your CPU, not Fx.

I found that the unhappy solution is to ...make sure that ActiveX is fully enabled. Then use IE.

You should only do this on sites that you trust completely, since ActiveX is extremely dangerous. It opens your entire computer to the mercies of the Web site.

There is an ActiveX extension for Fx that implements just part of ActiveX, mainly for use with the Windows Media Player. It's supposed to be safer. But since you have already opened your computer to this Web site, you might as well continue what you are doing and not open Fx up any more.

On the other hand, if it works and is not too slow, 40% isn't bad. You might consider just using it. You still have the other 60% of a fast computer, and that's a lot more computing power than I have on most of my computers.

[schapel]

The results are that in Firefox, my CPU utilization is around 40%, with a 10% fluctuation up and down. Testing with IE, my CPU utilization is 2%.

<b>That's because the Flash plugin for IE is a different program.</b>

No, it's because that page demonstrates something that is actually inefficient in Firefox -- JavaScript moving scaled images. In practice, it doesn't seem to cause many pages to use lots of CPU in Firefox.