Tuesday, April 28, 2009

SOLUTION: High CPU usage (even) in Firefox 3.5 b4

I installed Mozilla Firefox 3.5 beta 4 latest nightly build from the Mozilla FTP site wanting to test the bleeding edge of the browser. I was hoping that with this release, Mozilla would have made a giant leap with a lot of previous bug fixes in place, specially the resource hogging one. On install, Firefox automatically imported my plugins, settings etc. from my previous 3.1 version to give me a smooth usage experience. All was good, or so I thought.

After a while I started seeing Firefox using a LOT of CPU.


I tested this again by closing almost all my Firefox tabs, except about 2-3. I now had just GMail, Google news, Google search, and a one article open, but still I could see Firefox using upto 20% CPU. A pattern I noticed was that the CPU usage was going up and down every few seconds. So the CPU hogging was happening intermittently.

Not loosing faith on Firefox yet, I searched the net for any possible solutions. I tried Flashblock, I changed the urlclassifier.updatecachemax setting, but all in vein.

Then, on an intuition, I disabled by WOT plugin.


The high CPU usage vanished! WOT, or the Web of Trust plugin has a community of fellow users who rate websites. As we visit any site, it's WOT rating gets displayed. Also, when we visit a site such as Google search or any other site, WOT scans the page for any links, and shows the link's WOT rating. Perhaps this algorithm is causing the excessive CPU usage. Maybe this is happening to me only. What I know is, this was the cause of problem in my case.

Here is a screenshot of the CPU usage now


Now that I think of it, maybe installing plugins which rate/check every link on a website is not really that good for performance(duh). Even plugins like StumbleUpon do it, so maybe there is a performance penalty too. All's well that ends well, is all I'd say.

Do leave a comment on what you think, and if this article helped you too.

3 comments:

Sami said...

We are unable to reproduce the problem with WOT. Try creating a clean Firefox profile and install the add-on there. It should rule out any conflicts with other add-ons.

Prateek said...

I have exactly the same proble. I uninstalled most add-ons, but the problem persists. I think it's not a issue with WOT because I hadn't installed it. I think it might be a problem with one of the addons. Can you help me narrow it down? Did you have any of these installed at that time? Yoono / Stumbleupon (disabled)/ Autopager / Brief / Foxy Proxy / FEBE. These are the major suspects. Drop me a mail at prateekmi2 at gmail dot com if you can. Thanks.

Anonymous said...

The problem also appears in Chrome and IE. I've solved it by collapsing the Google Chat module as described here: Click.