Alienware Aurora mALX User Manual page 48

Alienware Aurora mALX Technical Reference
Each Windows power plan will also adjust the processor performance of your machine
in order to save power. This is worth bearing in mind if you are experiencing any
reduced performance (especially under DC/battery power).
Choose High performance for maximum performance when the computer is powered
from an AC power source. Choose the Power saver (bear in mind that this scheme
may slow down the overall performance of the computer in order to save power) for
maximum power saving when the computer is battery (DC power) powered.