Hello Tim.

I cannot reproduce this issue on my end. Please contact Adobe for support, as it's most likely something wrong with their plugin.

I did contact Adobe for support, they had me uninstall/install Adobe and try again. I had the same problem,lag time playing Happy Aquarium on Facebook. But no problem using google chrome(which i dont like on my computer), i even put IE back on my computer to see how it would act,no problem there. I have used Mozzila/firefox for years and that has been the only broweser on here,never had a problem before. Could this be related to WINdow7 ? I have a HP,with amd quad core processer with 12 g of ram.

I don't know, Tim. The fact is, you're definitely not the first person to experience issues with Flash, and they relatively common, and have been for years. Alas, Flash has gained a reputation for being buggy, heavy and unstable. In fact, it's tendency to crash is the main reason for Mozilla implementing plugin isolation, as a stability fix for Firefox.

As I said, I cannot reproduce this issue on my end, so I can't possibly know what's causing this, and, again, Adobe support is much more qualified than me in that point. I do know that Flash 10.1 (the latest version) has hardware acceleration, and that tends of be a problem on some hardware. But if it's just Firefox that's causing the problem, it might be something specific to Firefox that's causing the issue. I suggest you try disabling all add-ons (extensions, themes and plugins) except Shockwave Flash and see if the issue go away. Please report back the results.

I disabled Ad block plus. Seemed to remedy the problem in a major way.

Everyone can blame flash player if they want, but the truth is for me I went from an earlier version that had plugin container which created lag for me. I disabled the plugin container in about:config settings, and firefox worked fine. Plugin container screwed up any videos i tried to watch on the internet by freezing, lagging, and crashing firefox. I was fine after I disabled plugin container, but then eventually some time later down the road I received a warning that i would soon be forced to update my mozilla so I eventually/reluctantly gave in and complied. At this point the same problems started again!!! I disabled plugin container again and it did help a bit right away. But this version 12.0 even with plugin container disabled with just a few tabs open I receive choppy video (like a snapshot of the video at 3 seconds in, and then another snap at 6 seconds in) I'm only seeing snapshots of the video like every 3 seconds while the audio continues on fine. That"s how bad the lag is. This is horrible performance for a browser. If I try to load a video while one is already playing, just that little bit of stress (2 youtube videos open at once) is all it takes to crash this poor performing version of firefox. I mean I can't even close the tabs after these situations and the audio sometime runs after closing for me as well. These problems did not start until the version changes of firefox and the addition of plugin container, not flash player. I have been a loyal mozilla fan, but my patients is wearing so so thin with the performance of this browser at the moment. Unfortunately I just realized for the first time ever I actually have to (against my will) install another browser just to watch videos. How sad is that? Considering watching videos is one of the main uses of a browser, I consider this version a failure. How could I not??? I guess I have no choice but to Chrome it up. I hope a fix for this problem can be found soon for I miss the great performing days of this previously top performing browser. Fingers Crossed!!!

Assuming you have Flash Player 11.2 or higher installed, have you checked for any updates to your video driver or sound driver?

Recently after update of flash player, I got problems with youtube , then I downloaded older version of flash player 9.0.47.0 and installed it , all problems were over, Google for apps old versions 9.0.47.0 , to find it., may be other older versions also work......Every time something is updated, check your youtube playback ,if something is wrong, then you know what caused it