Firefox 3.5 Slow Startup

Posted July 8th, 2009 by kyle

I switched to Firefox 3.0 a few months ago, and I was looking forward to the release of version 3.5. It’s supposed to have a much faster JavaScript engine and some other nice improvements, but unfortunately Firefox 3.5 startup time is much slower than 3.0 (which wasn’t very fast to begin with). A cold start of Firefox 3.5 on Windows XP SP3 takes about 25 seconds vs. 8 seconds for 3.0. A warm start is about 3 seconds vs. 1 second.

This was just too painful for me (and the suggestions to cleanup the TEMP folder and IE cache didn’t help me), so I switched back to 3.0 for now. Apparently I’m not alone in experiencing this, so hopefully they’ll get it sorted out soon. I always appreciated Internet Explorer’s blazing startup time (about 1 second for a cold start and almost instantaneous for warm). Maybe they will finally make it a priority to improve on startup times in v4.

Update: I was able to get v3.5 cold startup time down to 9 seconds by following the instructions in this article. IE’s cache cleanup must not be very comprehensive, since there was still over 67MB of files there.

Share and Enjoy:These icons link to social bookmarking sites where readers can share and discover new web pages.
  • BlinkList
  • blogmarks
  • digg
  • feedmelinks
  • Furl
  • LinkaGoGo
  • NewsVine
  • Reddit
  • Simpy
  • Spurl
  • YahooMyWeb

One Comment on “Firefox 3.5 Slow Startup”

  1. Chris Sutton Says:


    I just upgraded to FF 3.5.1 and it and my cold start time went from 45 seconds down to 10.