Power
Software Guide 1–13
Processor Performance Controls
Windows XP Home and Windows XP Professional provide
unique software that allows the user to control processor
performance. The CPU (central processing unit) speed can be set
for optimal performance or for optimal power conservation.
For example, the software can be set to trigger an automatic
change in processor speed when the power source changes
between AC power and battery power, or when notebook use
changes between active and idle.
Accessing Windows XP Processor Controls
To access Windows XP Home and Windows XP Professional
processor performance controls, select Start > Control Panel >
Performance and Maintenance > Power Options > Power
Schemes.
The user sets the desired Power Scheme and that, in turn, sets the
processor controls. Each Power Scheme for AC power or battery
power equates to one of the following processor levels:
■ None: Always runs at the highest performance state.
■ Adaptive: Performance state is selected based on CPU
demand.
■ Degrade: Starts at lowest performance state, then uses linear
performance reduction (stop clock throttling) as the battery
discharges.
■ Constant: Always runs at the lowest performance state.
