You may try to disable the automatic adjustment for the TCP window size.
This link may help.
Vista Slow IssuesVista business slow accessing domain resources ... I have a
mix of machines running on an SBS domain. (XP, Mac, and Vista > > business)
Two are Vista . ...
Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on
How to Setup Windows, Network, VPN & Remote Access on
"Nuno Azevedo" <NunoAzevedo@discussions.microsoft.com> wrote in message
> when i copy a file with 5mb in win xp from win2003 server copy in less 1
> minute and with win vista business copy in 30 minutes or more. the test is
> various pc's.