CDan, I don't mind wasting a few discs but should they be DVDs or CDs for testing (I would assume DVDs since that is the problem area.)
However, I just installed the new SATA harddrive an hour ago and ran a DiskBench test on the drive. This test was run with the drive attached to the USB highspeed hub, NOT to the unused port I generally use for the burner. I think it did quite well. (I will run another test using the other port and compare)
Based on this test I can only assume that the chipset of the enclosure I am using for the burner is the culprit for slow transfer rates.
Here is the test results on the new harddrive.