For some reason when I watch movies on VLC on my mac, they lag really bad (not the audio though) and they make the rest of my computer lag too.... any way I can fix this or prevent it from happening?

does this happend with other players? like Bsplayer?

Are the videos high definition?

is the vlc + card up to date?

try get another media player maybe?
i once lagged at every movie then just downloaded another player and no problems

It happens on vlc and quicktime, also on online things when I stream. The videos are not high def, they're usually low def.

up