Last night I ran a little test. I took 150 images on mhy 5D Mkiii in Raw (about 26mb each file) and then transferred them onto an unpowered portable external drive via a) My Lenovo P400 with one USB3 and a USB 2 port, weight 5 pounds, b) a 5yr HP pavilion with 2 usb ports weight 7 pounds and a core2 duo processors and c) an Asus eeee netbook my girlfriend owns which weighs 3.5 pounds with 2gb ram and atom processor. After each test, I reformatted the external hard drive so same space available. The Lenovo did the transfer in 4min. 50 sec., The old HP took 10m, 30 sec., the Asus netbook took 8m, 40 sec.
What does that tell me? I'm assuming the fastest transfer was due to the one USB 3.0. I expected it to be the fastest. I was, however, surprised that the tiny, cheap netbook could beat the HP. so surprised, I re-ran the test. I still believe even the smallest weakest device will do a fast transfer if it's got 2 USB 3 ports. The search continues, but this was a good start.