Let me say that even Microsoft doesn't provide a digitally signed driver, whatever.
The solution ekko suggested drastically improves performances, I tried with modified .inf files on a second pc, and the situation now is correct.
This is a hint for everyone: to test a usb3 properly we need a fast chain, ssd with os installed, usb3 port (and decent drivers), usb3 pendrive or external ssd.
'Till you stay on mechanical disks there's no way to reach the limit, 'cause we moved from 480 Mb/s to 4.8 Gb/s bandwidth, but you can always see the difference; and as Bowie wrote, a good external case is mandatory.
This is my second test on a Vaio with Ivy Bridge ecosystem (HM76 vs Z77).
