A customer was complaining recently that the file copy performance from their Windows 7 PC to one of their Unix boxes was dreadful. But file copy performance was ok if they were copying to a Windows Server. The customer was kind enough to provide a network capture so I could see what was going on.
Looking at the network capture, I saw that communications to the Unix boxes were using the SMBv1 Protocol, and the communications to the Windows Servers were using SMBv2.
If you Google “smb performance windows 7” you’ll find lots of complaints about Windows 7 being slower than Windows XP for Samba file copies. It appears that SMBv1 file copies are in fact slower with Windows 7.
The solution I suggested to the customer was that they upgrade the SAMBA version on their Unix boxes to a version which supports SMBv2. In particular, the “durable file handles” feature will fix their issues. This SAMBA wiki page has further details.