Recently, I found my Firefox is crashing very often and take up lots of CPU time. At first, I thought there are some virus or Trojan horse hijacking my browser. After I run extensive anti-virus scan and found nothing. I am suspecting it is the fault of the add-on. I completely uninstall Firefox, deleted all the add-on I have downloaded over the years. I reinstall a clean copy of Firefox. Viola! It is running lighting fast and I have no more crashes.
I slowly adding back some useful add-on, trying to limit myself not to install add-on that I never use. Add-on that stays inactive until invoke by me are fine. Those are most productivity tools. I tends to stay away from any add-on that mess with the rendering engine or trying to modify the page on the fly. I found those add-on really slow down Firefox. In some cases when the connection is patchy, it may even stuck in an infinite loop and lock up the browser. Sometimes more is less, sure is in the case of installing add-on. Actually, it is true for all software project. Any feature you don’t need slows the software down. Load up the software with tons of useless feature make it crawl like a snail, Vista is a perfect example.