Mac

Got identical results WAN or VPN LAN to LAN . 1472 ok, 1473 not ok.

Will put them both to 1492 when I return from leave.

Thanks.

admin wrote: Yes, but my point is that it might be a Windows inefficiency hence the suggestion to measure raw transfer speed. There are also tools to measure throughput.

This is a well known problem with Windows file sharing. The older versions of the SMB protocol (which is used by Windows) are very chatty and do not work well with WAN connections where there is latency (i.e. most WAN connections).
Unless you are running WAN acceleration software (such as from SIlverPeak or RiverBed) or recent Microsoft operating systems at both server and client you will experience poor performance.
Google "smb v3 wan performance" and you'll find some information.

Thanks aweaton.

We are running Server 2012 both ends and most clients are Windows 8.1 or in rare cases 7 (but we've tested on our single Windows 10 Pro client and it's the same problem). I don't know if that's adequate for SMB performance and will have to look further into it.

Thanks.