I’ve read a lot of complaints about Firefox+Adobe Flash slow performance on Ubuntu (Linux in generally) (here and here), although I was alright (scroll down to timestamps 15:15, my nickname is c00l2sv) at the beginning with it, for several last days I gave up.
I wasn’t able to watch a flash trailer at all, so I said, there must be a solution…

The solution exists, tested by myself. Here’s where the power of Firefox add-ons and how accidentally found anti-advertising plug-in can save us!

Install Flashblock add-on for Firefox(3)!

How this works…
The problem (I believe), with the flash plug-in in use, is that it becomes very slow and starts to load dramatically much resources when it comes to render several flash clips on the same page or in different multiple instances with Firefox. So when someone is trying to watch a clip on a web page where beside the wanted clip the page loads a couple of other (advertising or most usually unwanted) embeds, the Firefox has to serve all of those, this way making the wanted clip “a slideshow” when watching it. Flashblock, does nothing but stopping all the page embeds before those would ask Firefox to be rendered. This way the computer resources are used more, intelligently I would say…

At least for me, problem is solved for the moment, but I definitely agree with the fact that flash plug-in needs a lot of optimizations on Linux!!!