Brand new WD1002FAEX only marginally faster WTF?

Ok, I’m running a Gigabyte GA-X58A-UD7 Motherboard with SATA3 connectors.  I recently purchased a WD Caviar Black WD1002FAEX 6GB/s interface drive in hopes of improving my drive score.  After installing and making sure I have the latest drivers for the SATA3 ports I see only a 3% gain in drive performance!  Anyone have any ideas?

3 GB/s is the maximum interface speed. The drive’s performance is determined by the sustained data rate from the platters.

data rate = sectors/track x bytes/sector x rotations/sec

According to the specs, the max sustained data rate for the WD1002FAEX is 126 MB/s.

WD Caviar Black Series Disti Spec Sheet:

You can use HD Tune to benchmark your drives: