ok, i should have asked my question in more detail:
i use PC (HP Compaq 8710p Business Notebook, specifically. so the PC is strong enough)
i've mass compiled as instructed on NXT Toolkit's readme file. compiling and downloading is fast but whenever i try to check how much battery is left or want to delete or upload a file from NXT each click of a button takes minimum 1 minute and the NXT Terminal totally freezes.
i can again mass compile (as i already did 2 times), but i don't think that it will help.
there must be something else or the NXT Terminal "by its nature" works like this :mansad: