Obvious question but have you downloaded and installed the latest drivers ?
It can be many months between the time some person at the factory throws a driver CD in the box and you buying the thing. Bugs happen.
Also, just to be sure....
......I assume you have taken the scientific approach and run the exact same benchmarking test on the exact same hard drive on your previous motherboard under the exact same background load conditions ? Otherwise you don't really have much basis for comparison ?
