Youtube and other video sites get choppy in Firefox

Ever notice an annoying, persistent lag every ten seconds or so when you’re watching a YouTube (or other) video in Firefox? Reader Bernard Sandberg has, and he’s written in with a smart about:config that solves the problem for him.

By opening about:config in your Firefox address bar, then typing browser.sessionstore.interval in the filter box, you’ll see a value of 10000, which is in milliseconds. (Meaning your session is saved every 10 seconds.) I changed this to 300000, or every 5 minutes, as I don’t have the urgent need for tab restoration. If you feel like being more on the safe side, try increasing it to something a bit lower, say 120000, or every 2 minutes.

http://several.amplify.com/2009/08/21/how-to-fix-annoying-youtube-pauses-in-firefox/