That's very strange... I did a comparison a couple years ago between Windows and several of the other accelerators (Fastcopy, Supercopier 2, Copy Handler, FF Copy, Ultracopier and a couple more, all that would be no cost for commercial use, which ruled out Teracopy) to see what they did locally and over a lan. It wasn't a double blind, duplicate hardware kind of test but it was the same sets of files and targets. In those tests Fastcopy was the clear winner speed-wise (although the interface is lousy, which is not an issue if you're scripting something). A few others were clumped behind that, generally not too far behind. Windows was never the fastest option, although some of the utilities were slower in some of the tests.
I don't have the details any more, but that said, the real end result is that I have Supercopier installed on my personal PCs. It was almost as fast as Fastcopy and does a good job with the management part that has been mentioned, and it has always been reliable. That was the surprising part to me -- with half of the other utilities I tested, I had issues with installation, lockups or copy failures. To my mind that immediately ruled them out.
That was back when I could do stuff like that for my previous employer. I can't recall if was running XP or 7 at the time, but would have been 32 bit in eiother case. Would probably be worth revisiting.