That's the virtualized controller Windows uses for drive pools (if you set them up). Try looking under "IDE ATA/ATAPI controllers" instead of "Storage controllers".
Just reading back and my reply to gavinh87 was wrong. The "Standard SATA AHCI Controller" is under the IDE ATA/ATAPI Controllers section of Device Manager. After using AS SSD it shows the driver as the MS storahci one. Do AMD not have any drivers like Intel (iaStorA) boards have or do they just rely on the MS ones? Curious more than anything cos the speed tests are the same as on my Z77 board.