I Have your X8DTL-3 together with 3 pieces HDD called WDC3000HLFS (FW:04.04v01)
With the onboard ICH10R SATA RAID controller,Using Intel the FW, I created a RAID 5 and Installed Windows 2008 R2 on it.
Now if I copy a file for example of 3GB on the same physical drive, I got a very low throuhput, a3GB file copy takes around 6 minutes?
Please make sure to install latest Intel Matrix storage manager and enable the cache write-back option in the Matrix Storage Manager,also update the FW of your WD harddrives to 04.04v02, now you should see a large increase in throughput.