i have 1000 clients(host) spreadly in my country and for some reasons i want to know their connection speed. how do i can get it?
All of my clients are using Windows.

You can't really get the port speed of their system without logging into the system in question. You can check to see how well they respond to internet requests and the path between you. Look into MTR (aka WINMTR) which uses trace route and ping to give a server to server route evaluation.