August 07
Solving Firefox slowdown / high CPU utilisation
I really like Firefox, especially version 3's excellent address bar, I really miss that in IE 7. Unfortunately both Firefox 2 and 3 seem to suffer from random high CPU utilisation. Not only does this slow down my system, but it has the annoying side effect that all system fans spin up.
I am able to reproduce this on several different operating systems and hardware platforms including a MacBook, VMWare, Vista, XP and Windows server 2003.
The problem appears to be Flash related (I run the latest version 9.0r124) as disabling Flash (Tools / Options / Main Tab / Manage Add-ons / Plugins tab / Shockwave Flash) makes the problem disappear. Unfortunately it makes all the nice Flash technology disappear as well.
It must be related to the way Flash Interacts with Firefox as IE7 on the same machine does not suffer from the same problem.
Update: The web without Flash is broken nowadays. Rather than disabling Flash in Firefox I now use the Flashblock extension that automatically disables all Flash content (whitelists allowed), but still allows the content to play when clicking the placeholder.