I read manual and found this:
When this item (Onchip SATA Type) is set to [AHCI], only SATA connectors 1-4 can be detected. Ensure that you've installed the AHCI driver, so that you could use SATA connectors 1-6 in AHCI mode under OS.
But as I said earlier I have 3 hdd in raid 5 and to make they work "Onchip SATA Type" is set to RAID and I can't change this to AHCI or IDE.
Any other idea?