No doubt, AHCI Rulez!!! Testing in my mobo, Gigabyte P35 DS3-L, Seagate 3200.10 320gb Sata 2 16mb cache: Copying folder 793mb from partition to desktop: - Without AHCI, Sata drivers, Write cache enabled: 52 seg. - With AHCI, Intel Storage Manager drivers, Write cache disabled: 39 seg. A big difference, INMHO... The only drawback in AHCI mode is that i can't enabled write cache (is grayed out) Greetings from Spain