About Automatic Processor Performance Setting

Learn what automatic processor performance is and how it can save energy and battery power.

This article has been archived and is no longer updated by Apple.

Setting your processor performance to automatic allows your computer to save energy. When you turn it on, the microprocessor's voltage, bus speed, and clock speed are adjusted to answer the current demands on the system. The advantage of this design is a longer battery life on portable computers and fewer running fans on desktop computers because of lower operating temperatures.

If you are using professional applications, games with intensive video processing, or other applications that use the microprocessor intensively, the Automatic option in Energy Saver may not provide the best microprocessor performance. If you know you are going to be placing a significant demand on the microprocessor, change your Energy Saver setting to Highest.

Selecting the Energy Setting

To set processor performance to automatic in in Mac OS X v10.2, Mac OS X v10.3, Mac OS X v10.4, and v10.5:

  1. From the Apple () menu, choose System Preferences.
  2. From the View menu, choose Energy Saver.
  3. Click the Options tab, then choose an option from the Processor Performance pop-up menu.

Automatic: The microprocessor will change speeds based on current demands.

Highest: The microprocessor will run at the highest speed.

Reduced:  The microprocessor will run at a reduced speed.

 Above: Energy Saver settings in Mac OS X v10.2.x

Above: Energy Saver settings in Mac OS X v10.3.x 


Above: Energy Saver settings in Mac OS X v10.4.x and v10.5.x


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