My notebook is Asus U46E has one USB3 port. I tested the write speed of USB3 in Ubuntu, it's fast as my expectation without doing anything. But when I go to Win8, the data was written in not-right-speed of USB3. I had tried to install drivers from Asus. It's still the same.
EDIT: In the benchmark, I see the read speed is good. Write speed did not pass 15MB/s.