Lags 3 GB of RAM\twitch
When viewing Twitch.tv (maybe not only) accumulates the RAM memory, the problem disappears after the restart of mozzila, but still it's not normal. http://i.imgur.com/B9CmFo7.png
Opaite Mbohovái (1)
Well the Flash Player Plugin can cause a lot of memory usage over time which one of the many reasons people do not like the Flash Player Plugin.
The good news is Twitch is moving to using HTML5 for the video part of player (already had HTML5 for chat and controls for over a year now) soon as they are currently in Beta testing. https://blog.twitch.tv/html5-beta-access-expands-99554ea982e4#.kgonqf5ek and https://help.twitch.tv/customer/portal/articles/2477288
The Flash Player embed is being depreciated as of Aug 29. https://blog.twitch.tv/flash-player-embed-deprecation-73a5df60f0df#.k1udqd8eh
You can try to view streams with the html5 player with say http://player.twitch.tv/?channel=channelnamehere&html5 (replace channelnamehere with channel) however there is no chat so you would have to say open a normal twitch stream and have chat change to a popout for example.
The browser is Mozilla Firefox or most call it as Firefox for short.