Mac computers SMB versus AFP
Recently while performing some tests, we have confirmed that Mac to Mac or Mac to Unix or Mac to PC, whenever AFP is available, file transfers appear to be more reliable and occur faster. Not faster than a Windows to Windows SMB transfer, but rather faster when compared to a Mac to anything transfer using SMB versus AFP.
So if your SMB transfers for your Mac seem to drag, consider switching to AFP, which is available on Mac, Windows and Unix servers.