Earlier this year, I purchased the above motherboard. It was advertised as supporting SATA 3.0 on its AMD SB850 controller, with speeds up to 6 Gigabits/s. I didn't have any SATA 3.0 devices at the time I purchased the motherboard to test with . I do now - two hard drives and two solid state drives.
Much to my dismay, I was initially unable to achieve these speeds. The burst speed in popular benchmarks such as HDTach topped around 200MB/s, which was clearly SATA 2.x 3 Gigabits/s territory.
After much googling, I found that I was not alone with the problem. Fortunately, I found that a beta BIOS update from Gigabyte, version FGf, solves this problem. But it took many hours and grief to figure it out.
The beta BIOS did introduce another problem, though. When using AHCI mode on the AMD controller, the machine would no longer go to sleep under Win7. More precisely, it would go to sleep and immediately wake back up. The fix was to disable "USB wake from S3" in the BIOS. I didn't have to do this before. It isn't required if I use RAID mode on the SB850 contrller, either. Just another BIOS bug. Hope this will save somebody else time.