Safari6.0.2 When I use Facebook or any site with flash content, safari hangs for sometime

Safari6.0.2 When I use Facebook or any site with flash content, safari hangs for sometime and when it reloads or force reload all my accounts gets signed out

and if there is any download going on it stops the download, and problem specially regarding Facebook the right side bar that shows notifications it tends to lags and sometimes after image stays behind.

How to correct all this?