In the BIOS do not see an option to enable or disable the RAID.
There is an option called: RAID/ATA &SCSI BOOT ORDER
They are:
SATA1,2,SCSI,SATA3,4... (DEFAULT) My BIOS has been using this.
SCSI,SATA1,2,SATA3,4... I have tried this.
SATA3,4,SCSI,SATA1,2... I have tried this.
What I have not...