So, if your software slows down (atleast t20) totally when it uses com port, next thing is the sollution.
Set com port's speed from windows to a 115200 and you're ready.. I don't know have I reduced this setting or have not. But it was it.. Now it's same as my old 600 seris used to be. It was not funny when almost three times faster computer is so slow at same light software on both computers =)



