I have no idea why my 890GPA -UD3 beats the hell out of the 970A-UD3 on the on-board SATA department too as it s the same southbridge
I have bought the 970A-UD3 to move to FX CPU-s smooth, but when to sell the older board i came to the conclusion it would be a waste ,waited almost one year for BIOS fixes and i have simply gave up.
On the other hand FM2 boards don t have issues it seems in the storage area.
RMA it maybe you get a proper one.