Yep, actually, I think it's the equivalent to unplugging a laptop from AC power and running on battery. The unit will lower power consumption by running at a lower FSB and on certain laptops, turn down the backlight on the LCD (like my Sony PIII laptop.)
Drat dragon beat me to it. Cool and quiet is just an automatic turbo switch.
Of course as the old farts know the turbo switch was for compatibility for the early DOS games which were timed based on cpu clock speed, not system clock speed. WHee pac man on a 16mhz AT instead of an 8 mhz pc took some helacious fast reflexes.
you think that's bad...... try Scorched Earth on a processor in the couple hundred Mhz or 1Ghz range. THAT is some wicked stuff. take like 10 minutes just to adjust your angle and power. or just set it to all computer players and watch the carnage end in seconds.