Got to love it when they say that.. Lol..It's all cat5e.
The drives are both SATA. The read/write times of the NAS should be the same as the actual drives since they plug right into a SATA controller.
I've contacted D-link and linksys about their respective enclosures and they are saying that the drives seem to be setup right and that they can't help me...
I don't know enough about that particular one to be able to help you much.
Have you tried changing the network. I know you have tried different cables and places. But was it all setup the same way?
If so could you go into detail of how your network is setup.