Unfortunately reduces the data rate

I been a few weeks now use the cable to extend more to the work surface, as my USB 3.0 ports on the PC are unfortunately very unfavorable under the desk.
Unfortunately I achieve with the cable not nearly the speed, as I have when directly connected. If the data rate my hard drive normally between 80 and 100 MB / s, so it oscillates at the cable hanging only about 29 MB / s. This is still passable, with larger data sets I have to still go back to his knees to the waiting time for third abbreviate.