Hi,
like in BD IS 2010, the new Internet Security slows down significantly my Firefox browser. At the moment of deactivating the antipishing toolbar addon and restarting of the browser, there is much more speed and I haven't to wait for loading sites anymore.
Cache and Cookies are cleaned up, Windows 7 64bit System is fresh and 1 week old, so it's because of the BitDefender Antipishing toolbar. Just want you to know that.
regards