Matthew,

Lets gather some more details about your environment...

Any additional components of the client installed?
What protocols are bound to the client?

Windows Event logs showing anything unusual?
Was Windows installed from scratch, a custom image, or an OEM image?

Security or any other driver-based software like firewall, VPN, remote
management or antivirus installed and running?

Take a look at this list and let us know which, if any, of these steps help
with your delay...

Enhance Client32 Performance
http://www.ithowto.com/novell/clientspeed.htm

Can you verify the issue is still present with the latest update on client
4.91?...

Production patches for 4.91
http://support.novell.com/filefinder/20609/index.html

Beta patches for 4.91 (beta can be better in some cases than production)
http://support.novell.com/filefinder/20609/beta.html

--
Tony Pedretti