ftp vs windows copy

Hi,

Does anyone know where I could go to find accurate data regarding windows
copy vs ftp speeds, overhead on windows copy, etc? I have two offices and
one office needs to copy fairly large files off of our server over a T1. We
seem to be seeing pretty big differences between the speed of FTP/HTTPing a
file vs just copying it.

Also, we are looking to sync these servers at some point in the future. The
file deltas on one server are around 2GB/day, what is the best method to sync
these?

Thanks for any info