I have 2 500 GB Simpletech powered, a 1 TB WD powered MY Book, and a 2TB WD powered My Book. They are all 2.0 USB. I have them in a 4 bay hub . I am lazy so I also bought 5 X Wireless Remote Control AC Electrical Power Outlet Plug Switch. So I use the remote to turn the drives on and off 3 at a time to meet the Hopper 3 limit. If the H3 ever allows folders, I will be able to reduce back to 3 EHDs and eliminate the hub.