The USB3 drive is just an external casing. Dollars to donuts its just a regular old sata 2 drive in there
Specially since they offer 1, 1.5 and 2 TB options. Trying to find out WHAT hdd is in there right now... guess a lot of reviewers are scared to crack it open and look
EDIT: yeah no one has opened it I did find a review saying it is a 3.5" drive inside though