You need RichCopy.
From Joshua Hoffman on TechNet Magazine: RichCopy is a free utility that comes to us from Ken Tamaru of Microsoft. The tool was first developed in 2001 and has been updated regularly to keep pace with evolving needs. Trust me when I tell you, this is the answer to all your file copying needs. What you’ll find most striking the first time you take RichCopy out for a spin is that it’s a multithreaded copying tool. That means that rather than copying one file at a time in serial order, RichCopy can open multiple threads simultaneously, allowing many files to be copied in parallel and cutting the total time required to complete the operation several times over. You can also pause and resume file copy operations, so if you lose network connectivity at any point, you can just pick up where you left off.
– Thanks, Jinesh.