Cannot install operating system in RAID mode with 3TB hard disk drives.
Kindly follow the instructions below:
Set up BIOS options:
a. Set [Peripherals] > [OnchipSATA Type] to [RAID].
b. Set [Peripherals] > [OnchipSATA port 4/5 Type] to [As SATA type] (may vary by models).
c. Set [BIOS Features] > [OS type] to [Other] if you are using Windows 7.
Set [BIOS Features] > [OS type] to [Windows 8] if you are using Windows 8.
d. Set [BIOS Features] > [Storage Boot Option Control] to [Legacy First].
Save and exit then set up RAID BIOS (you may refer product manual for detail steps).
Reboot, press [F12] to enter boot menu and choose UEFI device.
Install operating system and load latest SATA RAID / AHCI driver from product page.