Hello. I have a Late 2011 MacBook Pro with Thunderbolt and USB 2.0. I have a Belkin Thunderbolt Express Dock that has 3 USB 3.0 ports. Connected to them I have a Segate USB 3.0 External Drive. The Read/Write speeds are around 40MBps read and write. Plugged directly into a MacBook Air that has 3.0 I get just over 80 MBps. Is this normal? Should I get higher speeds? Isn't USB 3.0 supposed to be around 640MBps? I understand that the dock may not do better than 320MBps but I was hoping to get a bit closer. Thanks for any light that can be shed on this for me.