Since version 2.0, Firefox has a session restore feature which enables you to continue browsing from where you left even if you restart the browser. Firefox achieves this by periodically saving the status of all open tabs to the hard disk. In the event of a crash or computer shutdown or any unnatural termination of Firefox, the browser is able to restore the browsing session from the last saved tabs status.
By default, the time interval between each session save is set at 10 seconds. If the number of opened tabs is high and the web pages loaded on these tabs are heavy (images, Flash etc), this periodic saving of session can cause Firefox to momentarily stop responding during each save, every 10 seconds. You might not notice this during casual surfing but if you are watching an online video such as those on YouTube, you might notice this irritating, repeating glitch.
Most users attribute choppy videos to poor Internet connection, but in some cases the problem might lie in the browser’s small session-saving interval.
Increase the interval, of course. To do this.
- Type about:config into your address bar.
- Read the notice and click the mandatory "I'll be careful, I promise!"
- In the “Filter” box type browser.sessionstore.interval to locate this parameter. You can also get to it by scrolling down.
- Double-click on the item and change the value to 60000 (60 seconds). You can enter a larger or smaller value if you wish, but remember that a large value means less frequent saves and higher the chance of losing opened tabs in case of browser crash.