Apple PowerBook (Duo 270C) - Manual (Page 119)

You may notice other effects of processor cycling. For example,
if you have open programs doing something in the background,
processor cycling may slow those programs down. You may also
notice that the Alarm Clock is updated irregularly or that the
wristwatch pointer appears more often. These changes do not
indicate a problem with your computer.
S Important: To conserve battery power, turn processor
cycling off only when using programs that it interferes with.
Turn processor cycling back on again as soon as possible.
S
Processor speed
The processor speed feature allows you to slow the computer’s
microprocessor speed (from 33 or 25 MHz to 16 MHz). Some
programs may work more slowly, but you may gain up to 10–15
minutes of work time before you need to recharge the battery.
(The amount of time you gain depends on how you are using the
computer.)
To slow the processor speed, follow these steps.
1. Choose Control Panels from the Apple (K) menu, and
open the PowerBook control panel.
2. Click the Custom button.
3. Click the “Reduce processor speed” checkbox to
select it.
4. Choose Restart from the Special menu.
The computer runs at the lower microprocessor speed until you
uncheck the “Reduce processor speed” box to deselect it and
restart the computer.
Chapter 6: Power Management 103