Whenever I have "Things going on" on my iMac, after about 2 hours the sound starts to slowly get worse and worse. When I restart it, sound is fine. I open up iTunes, I open up Firefox, I open a 2nd Firefox window, I start to download something, I open up VLC player, etc. The more I open, the worse the sound gets. It's like this static, crackling thing, like a stutter or as if it's buffering. Just because I have too much going on? It really doesn't seem like too much going on for a computer that's just a year old and has no problems. Sound card issue? But like I said, it seems directly related to the amount that the computer is doing.