I am not too sure I understand what you are asking. If firefox has multiple flash videos playing then some of those videos may show problems, it will depend somewhat on the computers abilities and your internet &/or WiFi connections.

You say you have confirmed it with others, if that was in an open public forum can you provide a link please.

Web searches can confirm almost everything http://lmgtfy.com/?q=elvis+is+alive the consensus may be that an alternative is likely, but if you search for a result you will probably find confirmation of it somewhere on the internet.

Don't know why you would need "proof" just because I found an issue being discussed elsewhere but here you go: https://bugzilla.mozilla.org/show_bug.cgi?id=711314

I'm just simply asking if others can confirm this issue to get it brought to a solution phase instead of the bug report sitting there as several have already confirmed this.

As I have already stated, this does not happen in IE or other browsers; therefore, it's an issue within Firefox. This also, proves that it is not a limitation of my "computers abilities" or my "internet connection" since other browsers handle it just fine.

I'm running a Core i7 with 8GB RAM and a nVidia GeForce GTX 460M graphics card. Here are the results of a speed test for my internet:

http://www.speedtest.net/result/1922627673.png

I am not looking for 'proof', although you appear to be asking for confirmation yourself and mentioned a discussion. You have now linked to a bug report from a single user that has remained unconfirmed and dormant. (Presumably you posted that bug ??)

Possibly it would help if you could provide specific steps with specific links that demonstrate this problem. Others would then be able to follow the procedure you suggest to see what happens. However I suspect the performance and results may be rather hardware dependant.

The bug report mentions

After opening around 6 the video in the flash player began to skip, 

that may not be unexpected, and may be rather an edge case rather than ordinary use of Firefox. (Possibly most users do not open 6 FlashPlayer videos simultaneously).

I asked the initial question because I was unsure what you were asking, and wondered if I could help confirm or otherwise your question. I do not think I can help; for one I do not use a computer with the requied spec.

I stated in my initial post, "This seems to be a random occurrence as I was not able to produce it again". It's only happened twice to me. Once I closed a couple of the tabs, the videos played fine. Trying to reproduce it has failed. Although the bug report (not by me btw...why do I feel like I'm having to defend myself?) said 5-10 tabs, I only had two opened. One from YouTube and one from another site, AnimeFreak.tv. Therefore, the number of tabs opened seems to matter not as many users would have two flash videos opened at once.

The possibility of the issue being hardware dependent is possible; however, unlikely as a google search would reveal this has happened off and on throughout Firefox's history. Especially after a version upgrade.

I'd also like to make note that whether hardware acceleration was on or off, it made no difference in the lagging of the video.