ASROCK 775DUAL-880PRO Manual To Installation And Configuration page 9

3. There are two methods to create a disk array. One
method is "Auto Setup", and another is "Select Disk
Drives". Select "Auto Setup" to allow BIOS to select
the disk drives and create array automatically. Select
"Select Disk Drives" to let user select the array drives
manually. When using Select Disk Drives method, the
channel column will be activated. Just highlight the target
drives that you want to use and press <Enter> to select
them respectively. When all drives have been selected,
press <Esc> to go back to the creation steps menu.