Periodically, when you turn on or reboot, not detecting hard drives in IRS Raid controller BIOS (Ctrl+I). At the same time Hard drives are defined in the MB BIOS without any problems. Hard drives six pieces WD2004FBYZ. When hard drives are determined normally, everything works fine. The power supply is changed. Sata cables changed.
CPU I7-6700K
Memory 64Gb
Video HD Graphics 530
PS 500W