My problem computer is a Mac Mini with a 1.42Ghz G4 and 512MB of ram. This is a problem that's been going on for quite some time now- during heavy CPU or memory use (either or), I get this earsplitting noise from any connected headphones. It sounds like a sharp and low to mid toned synthetic noise, and plays at full volume (very, very loud!) It lasts for a little less that 1/4 of a second, but it leaves my ears aching afterwards. It just happened today as I was using iMovie. It happens very rarely. Can someone please give me some advice to get this problem taken care of? Thanks.