|Look in the BIOS again to verify the setting is still set to Enhanced. |
If it is and you performed a completely fresh (no over the top) install of Windows 7 then the SATA controllers are running in the SATA mode.
Don't pay too much attention to how the drives are listed. Run the burst speed test again and see what you get.
One thing that can affect the SATA performance is, believe it or not, a sharp fold in the data cable. If it has been folded too tightly, unfolding it may not fix it. There is shielding inside the cable and just like coaxial cable on your TV can be damaged that way, so can the SATA data cable.