Your PDC emulator may experience heavy usage if clients needlessly direct requests to it.
If other domain controllers at your site are available for authentication, you should set the LdapSrvPriority Value Name, a REG_DWORD data type, to 0xFFFF, because lower priority domain controllers will only be contacted when the higher priority domain controllers are NOT available.
NOTE: Clients cache their %LOGONSERVER%, so to cause them to forget the PDC emulator after you make this change, plan on stopping the NETLOGON service for about an hour during a period of heavy logons.
If you use WINS, its' default behavior is to add the PDC emulator, the <DomainName>(1B) record as the first entry in the list of domain controllers (<DomainName>(1C)) that the client searches.
To cause each WINS server to remove the 1B entry for the PDC:
1. Copy / Paste the following into NotePad.exe:
2. Save the files as DisablePrepend1BTo1CQueries.txt.
3. run regedit /s DisablePrepend1BTo1CQueries.txt.
4. Stop and restart each WINS server service.