Every time I'm watching a video(firefox, youtube, safari, VLC media player) the audio and video are not synced properly. What do I need to do to get these working correctly? Every now and then I get a pop up about cuda.kext, could this file be my issue? I have smccontrol fan installed. I also have a program called "boom", it's a volume booster installed. I've had these installed for a while and don't ever recall audio/video out of sync until a few days ago though.