Trying to decide between the base (dual core) or mid (quad core). Will be recording audio, so silent operation is a high priority. I am leaning towards the mid (quad core), but I'm concerned that the increased power for quad core will result in higher temperatures and fan noise. As I being overly cautious? Is it correct that the base (dual core) would be the more silent machine under normal use? I currently use a 2006 core2duo macbook, and the fans get loud with pretty modest web use. Any kind of video will set them off. Can I expect the minis to be silent under anything other than extreme stress (80%+ CPU usage)?