Advanced Host Controller Interface (AHCI) is the native work mode for SATA drives. It's been in the Linux kernel since version 2.6.19. Enabling AHCI has two main benefits: support for hot pluggable SATA drives (just like USB) and Native Command Queuing (NCQ).
SATA drives are usually configured as legacy Parallel ATA by the BIOS and the OS. Follow these two steps to enable AHCI:
First we have to add the AHCI module to the kernel image. We do this by editing /etc/mkinitcpio.conf and adding ahci to the MODULES array: