I have a new asus sabertooth 990fx build with a bulldozer 8150. I had an intel 510 which had no issues running at sata 6. My new Intel 520 drive randomly switches between reboots between 3 and 6 gbps sata connection. I updated my mother board bios to the latest, running ahci on all sata ports, using the 6 gbps ports not the marvel 3 ports. My dvd drive is on one of the sata 3 ports and I have a 1 tb sata 6 seagate drive on the sata 6 port which has no issues. Ive verifed the speed difference using as ssd and atto. There is a noticeable performance hit when its on 3gbps. Anyone else run into this issue? The fact that my 510 and seagate had no issues leads me to believe this is firmware related. I am also using an infamous sata 6 cable. Ive also tried switching ports to no avail.
I'm having the same issue with the drive conencted to a LSI RAID controller. Did you manage to resolve the issue?