Maybe it's because the hard drive was the bottleneck? What speed were you getting and what hard drive were you using? It common to just get 70MB/s on a big 7200RPM hard drive if your doing 2 things at once or the file you are transferring a fragmented file.USB 3.0 works great until you need speed. It does not come close to its 5 Gbs rating. It is pretty useless for hard drives. Would never use it over eSATA. Thunderbolt means I can do hard drives, external GPU, external video sources, and any other type of technology out there at a MUCH greater speed than USB in a realistic scenario. USB 3 is definitely better than USB 2, but not by as much as they claim.