try to update your firefox or for more latest version download firefox nightly

Hello TommyRay2013, Try disabling graphics hardware acceleration. Since this feature was added to Firefox, it has gradually improved, but there still are a few glitches.

You might need to restart Firefox in order for this to take effect, so save all work first (e.g., mail you are composing, online documents you're editing, etc.).

Then perform these steps:

• Click the orange Firefox button at the top left, then select the "Options" button, or, if there is no Firefox button at the top, go to Tools > Options.
• In the Firefox options window click the Advanced tab, then select "General".
• In the settings list, you should find the Use hardware acceleration when available checkbox. Uncheck this checkbox.
• Now, restart Firefox and see if the problems persist.

Additionally, please check for updates for your graphics driver by following the steps mentioned in the following Knowledge base articles:

• Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

• Upgrade your graphics drivers to use hardware acceleration and WebGL

Did this fix your problems? Please report back to us!

Thank you.

You might want to also disable the hardware acceleration in Flash, too.

(See this article for more information on using the Flash plugin in Firefox).

To disable hardware acceleration in Flash Player:

1. Go to this Adobe Flash Player Help page.
2. Right-click on the Flash Player logo on that page.
3. Click on Settings in the context menu. The Adobe Flash Player Settings screen will open.
4. Click on the icon at the bottom-left of the Adobe Flash Player Settings window to open the Display panel.
   
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5. Remove the check mark from Enable hardware acceleration.
6. Click Close to close the Adobe Flash Player Settings Window.
7. Restart Firefox.

This Flash Player Help - Display Settings page has more information on Flash Player hardware acceleration, if you're interested.

Boot the computer in Windows Safe Mode with network support (press F8 on the boot screen) as a test to see if that helps.

I've tried both things, but video still stutters.. Have also tried removing profile, and complete reinstall of firefox.

I'm on 24 Mbit cable and the only user atm. IE and Chrome seems to work without stuttering.

I've having this stuttering every ~5th second, like a small "1/4 sec buffering".

Hello ateriksen, in win 7 ?, try to disable the Protected Mode in Flash 11.3 and check it again, see also : Flash Player 11.3 Protected Mode - Windows.

thank you

Still some stuttering now and then, but that could also be network protocols that handles traffic.. I also tried removing cookies for the "problem-site", and It actually got even better. It's at least watchable now :) Great tip!

I have exactly the same problem. I use both FIrefox and Chrome together and although I love almost everything about firefox, what frustrates me the most is the constantly lagging video streaming. I have the latest Firefox version (ver 26) and the hardware acceleration is disabled. The videos even in multiple tabs will run perfectly smoothly in chrome but if I try n run even 2 or more videos in firefox, it will start hanging and the video will start stuttering. Any way this can be remedied?

I checked out the settings as you suggested and the "use hardware acceleration when available" wasn't checked so I checked it and restarted Firefox and it seems to have sorted the problem for me.