Note You can check the CPU and network usage in Performance Monitor.
Additionally, if the domain controller has the intersite topology generator (ISTG) role, ISTG updates trigger each Exchange server to perform a complete topology discovery, and that causes this issue to occur every 15 minutes.
Note This update can randomize the deferral time for Exchange to send out the LDAP queries of complete topology discovery.
Method 1Exclude the domain controller that has the ISTG role. To do this, run the following command in Exchange Management Shell (EMS):
Note If you want to remove the change that you have made and revert to the default behavior of Exchange, run the following command in EMS: