Could you 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!

iamjarakumars

I have done this, clearing my cache, changing browser.sessionstore.interval, making sure my drivers and extensions are up to date and not causing the problem, and even reinstalling the most recent Flash 11.

None of this worked so I decided to downgrade to the most recent Flash 10. It is a little better, but firefox still lags in the video and is jumpy sometimes when scrolling.

I may try and install an older version or Flash 11 or 10 to see how that goes.

Thanks for the reply.

Install Flash 10.3 and try it.

Download here

• http://helpx.adobe.com/flash-player/kb/archived-flash-player-versions.html#main_Archived_versions

You can check for problems caused by recent Flash updates and try these:

• disable a possible RealPlayer Browser Record Plugin extension for Firefox and update the RealPlayer if installed
• disable protected mode in Flash 11.3 and later
• disable hardware acceleration in the Flash plugin

• http://kb.mozillazine.org/Flash#Troubleshooting

As stated in my previous response, I am running the most recent (10.3) version of Flash now.

Problem still occurs, though not as often, and web pages with videos or flash items are very sensitive to scrolling, jumping around and lagging occasionally.

cor-el

-Not running RealPlayer.

-In 10.3 right now, I also tried to disable protected mode when I had Flash 11 with no success (forgot to mention I tried that also).

-Refer to previous comment.

Thanks for the reply.

Did you try to disable hardware acceleration in the Flash player?

• http://helpx.adobe.com/flash-player/kb/video-playback-issues.html

Flash "Display settings" window:

• http://www.macromedia.com/support/documentation/en/flashplayer/help/help01.html

cor-el

Ah, I apologize, I must have misread you comment!

Disabling hardware acc on flash player, help the video with youtube SIGNIFICANTLY.

There is some additional lag when i constantly move my mouse on and off embedded videos, but that shouldn't be a problem for me.

Thank you for taking the time to help me. Vimeo is still lagging pretty bad, so I will probably reinstall Flash 11 and try this out also to see if that works. If not I will stick with 10.

Thanks again.