I have my macbook hooked up via dvi to a formac 20" display. I've noticed the fans seem to be on alot of the time. I use it in 'clamshell' mode, although once ive started it up to just display on the 20" monitor, I do open the screen as I've heard it gets quite hot in clamshell. Should I be worried that the fans are on a lot? I have my MB sitting on a griffin icurve as well.