hi guys again.
Accually the problem still presists
Still some files have transfer 50mbits and some 300mbits.
I booted ubuntu live on my computer and transfers went up to 500mbit/s
i even bought another external 1gbit lan card, and the same thing (slow transfer)
(i am surethat this is nothing to do with slow hardrive !)
so, i think that this is not a nvidia drivers problem but windows 7 64bit problem !
still dont know the sollution for this problem