When you are connected to a Remote Desktop Services server in Terminal Services Manager, Terminal Services Manager actively queries the server for information about the users, sessions and processes running on that server.
If you do not need to monitor the users, sessions, and processes on the Remote Desktop Services server actively, you may disconnect from the server, just simply uncheck checkbox in server list on the left panel.
On the bottom part of the window there is a dashboard, where summary information about users, sessions, and processes is shown, also graphs by CPU Usage, Memory Usage, Processes, Sessions, Users, Active users, Idle Users, Disconnected Users, RDP Incoming and Outgoing Bytes for each server are shown.
Choose a tab above graph to view a parameter.