>X: is mapped to the directory C:\WORK. Not sure this is a network drive/share in your definition?

How was it mapped? Via "net use" command (i.e. mapping \\thismachine\work as X:) or via Subst command?

If it's the first, then it is using the network stack - it doesn't matter that it's on the same machine, it still goes through some of the network protocols. Being on the same machine may minimize the use of cable, but not the use of network related pieces of the OS.