Found the following when I browsed through the 10SP3 documentation:

If you are in a eDir environment and use DLU without any login restrictions then this might speed up your logins a bit:

Open the Registry Editor.
Go to HKLM\Software\Novell\ZCM\AgentSettings.
Create a String called DonotFetchUserGroups and set its value to True.

I got about 5 sec faster login, what did you get?