One of Mozilla's focusing with Firefox 3.6 was improving the startup times (see: https://developer.mozilla.org/devnews/index.php/2010/01/21/firefox-3-6-is-now-a

One of Mozilla's focusing with Firefox 3.6 was improving the startup times (see: https://developer.mozilla.org/devnews/index.php/2010/01/21/firefox-3-6-is-now-available-for-download/ https://developer.mozilla.org/devnews/index.php/2010/01/21/f... http://autonome.wordpress.com/2010/01/21/firefox-3-6-performance-startup-and-snappiness-improvements/ http://autonome.wordpress.com/2010/01/21/firefox-3-6-perform...). I believe they're going to continue to focus on this in future too -- I remember reading that some patches improving startup times have been completed but didn't land in time for 3.6, but I don't have a citation to hand. This matches with my personal expererience - anecdotally, Firefox feels noticably quicker both in terms of startup and rendering since updating to 3.6.