How to fix the video lag in Firefox!

firefoxLately my video (HD) playbacks in YouTube seemed to be lagging a LOT! I wondered why. I thought it would be me and my years old OS or perhaps even somehow my pc.

But no it wasn’t. The lag was caused by Firefox’s session saving feature. A simple and fast change in it and “poof” went the lag.

  • Open Firefox and type in “about:config” (without the “) in the Address Bar and hit Enter.
  • Type in “session” in the “Filter” line at the top of the list.
  • Find “browser.sessionstore.interval” and double click it. The 10000 milliseconds (equals 10 seconds) is the interval in which Firefox keeps saving your session in case of a crash; same amount of time between video lags.
  • Change it to something different. 120000 equals 2 minutes, 300000 equals 5 minutes or something else you desire. I went with 600000 (10 minutes), because I don’t particularly care about session saving.

28 thoughts on “How to fix the video lag in Firefox!

  1. Wow, that worked! However, I noticed that whenever I move my mouse, i also get a small lag. Do you have any idea how to fix that?

  2. I tried this but it didn’t work. The video will freeze every few seconds, but the audio continues to play. I changed it to 300000 and it will happen about every 4 – 5 seconds.

  3. Awesomeness!! That worked. Now if you could just tell me how to fix it for Chrome, I’ll be straight….We’ll I guess it did fix it for Chrome too. Double-Shot!!!

  4. Sometimes, you can also try switching a number from something huge to 0. It basically disables it. But it doesn’t always work of course, sometimes this means something different than you think. I’m testing it out now.

  5. Thank you so much i`v had to deal with that crap for almost 2 years.But as soon as i did as you told.It stop lagging 100 percent thank you so much.

  6. hi, i have just done the above and set it to the same number as you did, when i watched films before it would usually be alright for about 20 mins at a time but then lag constantly with no gaps. and then i would have to close the video down and put it back on and fast forward it to the spot that i was on for another 20 mins 🙂 so now hopefully it will have sorted it out now 🙂

  7. I’m on version 3.6.15. The above fix helped with the persistent lag a little, but i still had some slight lag every 10 sec. Changing the value for “” seems to have solved the problem. A browser restart may be necessary to see the improvement.

    1. Actually, the above change I recommended doesn’t help after all. Seems the restart helps, but that effect only lasts so long. Oh well, it’s not like anyone ever really uses flash these days….

  8. OMG… after all those years of rage and anger, FINALLY I have come across this. Thank you!!!

  9. It worked,but I had to set it to 40000 to get it to quit,seems to have downgraded the quality of the video and makes it look a tad compressed.

    1. This “fix” has absolutely nothing to do with video quality. It does not touch any compression nor quality variables.

  10. Thanks so much, Fixed the problem perfectly. The only video player I was having troubles with was Veoh, and now I don’t have the problem. I usually watch Subbed anime on veoh, so it makes it kind of hard to read the subtitles when it lags every 2 minutes.

  11. thx…. but after u leave ur comp for some time ur comp will be lag again…zzz

  12. The trick stopped working in Firefox 3.5.7! Sessionstore is still set to two minutes but the lags are back at 5 second intervals..

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