I've made some profiling and results show me that 96% of time is waiting the result from the HD. But I've seen also that the time between the moment where application send the io request and the time when this io request is processed was very long...

I've found that increasing task priority for the sbp2 task (and also Helios task) give me extra time and I've reached the same speed as USB2.0 one (for my setup).

Now, I try to see how to get more speed than USB