A very lightweight extension that allows you to watch YouTube™ videos using Flash® Player instead of the default HTML5 player.
The Flash® Player will consume less material resources (CPU, RAM) if your PC doesn't easily support HTML5 videos.
Why you should try it? Because for a lot of people the HTML5 player is laggy and causes playback issues. Once installed you have nothing to do and you can easily switch between both players if needed. Plus, this extension also works for embedded YouTube™ videos. Give it a try!