IIRC these warnings are often premature. I believe AVG is likely to flag the highest CPU process & highest bandwidth process. Often that will be Firefox. High bandwidth may be good it allows faster downloads and stutter free playback. It is the time it is used for that is the potentially costly factor. Using blockers & or disabling Flash and other media players unless needed will help because some material will be advertising or other material that you may not be interested in, for instance trailers on TV or other video clips on News sites. Some of your bandwidth will of course be necessary and you will benefit with faster file downloads and stutter free viewing or listening. '''Try to reduce bandwidth by opting for compressed files and lower resolution or smaller media files where possible.'''