Optical drives to my knowledge don't benefit from AHCI.
You have 2 controllers, Intel and Gigabyte.
1. Install SATA hard drives on the Intel controller and set it to AHCI.
2. Install Optical drives to the Gigabyte controller and set it to IDE.
Even if you did set all controllers to AHCI, double check the boot option and make sure that the optical drives are set as the first boot device.
Ideally, the hard drives take advantage of AHCI, so it doesn't matter whether the optical drive is set to AHCI or IDE.