For those of you who remember the old Terminal Services versions, sometimes, the remote session was suddenly frozen while trying to copy files, print files or do any network related operation. Windows Server 2008 included with a nice feature called “Display Data Prioritization”  that allows you as system administrators, the ability to control the percentage of resources allocated to  display, keyboard and mouse from one hand and  issues regarding file transfers on the other hand over the virtual tunnel session. Microsoft design by default that 70% of the bandwidth will be reserved for display, keyboard and mouse and 30% will be reserved for other traffic over the tunnel. Windows 2008 Display Data Prioritization is helps ,If this ration needs to be changed by system, administrator for some reason, the registry key to modify it is:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TermDD subkey
FlowControlDisable—This subkey Enables or disables flow control.
FlowControlDisplayBandwidth—stands for the bandwidth allocated for display, keyboard and mouse
FlowControlChannelBandwidth—stands for the bandwidth allocated for other traffic tunnels.