Benchmark tools may report slow USB performance on Windows Multipoint Server

The performance difference is due to how Remote Desktop uses low-level USB redirection. Windows Multipoint Server (WMPS) does not use the high-level drive mapping feature of Remote Desktop Service (RDS), which would, for example, expose your local C drive on the server as \\tsclient\c, etc. For Windows Multipoint Server this would not work because there would not be a way to isolate access to the volumes to a particular session. Instead, Windows Multipoint Server (WMPS) uses USB redirection which disconnects the device from the driver stack, inserts a shim driver that routes all of the I/O across an RDS virtual channel, then builds up the device stack for the device in a session-specific manner for the target user. We do the same for audio devices, cameras, etc. that are attached to the station hub.