I noticed today that my macbook air's performance drops significantly
when I unplug from the wall.  I assume it's cpu frequency scaling to
provide better battery life... but for the case of csound it leaves
the laptop unusable.

I've looked in system preferences and searched a little bit online but
can't find a solution... does anyone know how to disable the frequency
scaling?  I have problems rendering even simple projects at ksmps=10
while on battery.