You should connect your SSD to the first Intel port (SATAII_0) The Marvell ports SATAIII_6/7 are unstable, and have slow 4K speeds which are what really matter. The Intel ports are faster overall, more stable, and offer way faster 4K speeds
However, if you are set on trying the Marvell ports, yes you need to set the bottom ones to AHCI (Top settings are for the Intel)