There is an issue with File::Find (and hand-rolled solutions too) on win32 when working with mapped file systems. It will stat every file to determine whether it is a directory and needs to be recursed into. Each stat requires a server round-trip which can be slow.

If you call the DOS function you can do the whole thing in one hit. If you are certain the script will never be needed on a non-win32 system there is no issue with portability.

I was doing something similar a while back, and reduced the run time from several hours to under ten minutes.

-- iakobski