Well you've got some options:
First, you could just disable the Marvell Controllers and SAS as bobkn suggested. But then you could not use the ports.
Or, you could go to Advanced Tab > Onboard Devices Configuration > Marvell SAS Controller > and change the mode (that I am assuming is presently set on RAID) to IDE.
Or, if you want hot-swapping capability you could change the Marvell mode to AHCI.
To run the controller in either AHCI or RAID mode you may need to install the Marvell SATA drivers
. You will find the driver
on your motherboard Installation DVD, or you can download them from the ASUS website.
When you boot there will be a brief delay as the Marvell Controller is initiated (about 1.5 sec), but you will eliminate the delay as the computer searches for the non-existent RAID driver.
Sorry if my descriptions of the BIOS setup is different from yours. I am running an older P6T and my hardware is different than yours. Just post any differences.