Samsung SSD, AHCI Not Activated on SATA 6, Works on SATA 3

[techageguy]

New SSD 250G SAMSUNG 850 EVO on ASUS P6X58D Premium Mobo. When installed on SATA 6 port on mobo, Samsung Magician shows AHCI as Not Activated. AHCI is active in BIOS and drivers are installed. Magician speed tests are slow. Here's the kicker. When I move the SSD to a SATA 3 port, Magician shows AHCI as activated and test speeds are much faster.

AHCI should work on both SATA 3 and 6 so I am a bit confused and frustrated about not getting SATA 6 speed.

Running Windows 8.1 update 1.

Any ideas? Thanks in advance, Joel

 

[smorizio]

http://www.asus.com/Motherboards/P6X58DE/specifications/
the 6g ports are non intel ports that why.
try updating the driver for the ports.
if not pick up a known good pci sata card that supprots sata 6g. or it time to upgrade your rig.