Managing Displays: Displays and Display Calibrator Assistant
The Displays pane in System Preferences functions in a way that's similar to the Monitors control panel or the Monitors portion of the Monitors & Sound control panel of traditional Mac OS. The options available in the Displays pane vary with the type of display. For example, for a laptop with no other displays attached, expect only the Display and Color sections to be available. For an older iMac, expect to also have a Geometry section. Your system might have options not shown here.
In the Display section, shown in Figure 5.1, you can set the resolution, the number of colors displayed, and the refresh rate. There's an option to make the Displays information available ...