I have a few Windows 7 devices, and all of them have rather slow network drive access. You click on a share, and you see the green bar just hanging, and it's all rather annoying. Some quick searching around led me to a Windows 7 forum, and the fix was simple:
Go to the Internet Explorer options and go to Tools ->Internet Options -> Connections -> LAN Settings ->
Automatic Configurations: Make sure that "Automatically detect settings"
is unchecked.
Close Internet Explorer, and that is it..