when you want to watch the youtube videos, and you open the youtube videos in different tabs, Even you stop the youtube videos, the video buffering continues and your bandwidth is consumed to buffer other videos. This will lead to bad buffering of current Youtube video.
If you have good bandwidth aroung 2 Mbps, than its okay, you would not face any problem. But if you have 256 Kbps bandwidth than you have to suffer with youtube buffering.
so you can Stop Youtube Video Buffering :-
Just you have to Right Click on the YouTube video and select “Stop Download”