xcopy is a Windows command line file copy tool. I was suggesting that a sanity check for the performance of the code would be to manually do the same copy task using Windows system tools to check that the time to do to raw copy was the issue and not some overhead in your script.

Running the script using a mapped drive implies that the local machine is doing the work and that all the data it manipulates moves across your network connection. Running the script using telnet implies that the script runs on the remote box and all the data is manipulated locally to the remote box. It is the overhead of shunting large amounts of data across the network that I suspect is causing your issue.