|Red Hat Enterprise Linux 4: System Administration Guide
|Chapter 32. X Window System Configuration
If multiple video cards are installed on the system, dual head monitor support is available and is configured via the Dual head tab, as shown in Figure 32-3.
To enable use of dual head, check the Use dual head checkbox.
To configure the second monitor type or any of its settings, click the corresponding Configure button.
For the Desktop layout option, selecting Spanning Desktops allows both monitors to use an enlarged usable workspace. Selecting Individual Desktops creates a mirrored workspace effect, similar to laptops.