The Knowledge Consistency Checker (KCC) starts the first replication topology check five minutes after the service starts. Subsequent checks occurs every 15 minutes.

You can alter this behavior by using Regedt32 to navigate to:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\NTDS\Parameters

On the Edit menu, Add Value name Repl topology update delay (secs), as a REG_DWORD data type. The default is 300 seconds, 5 minutes.

On the Edit menu, Add Value name Repl topology update period (secs), as a REG_DWORD data type. The default is 900 seconds, 15 minutes.

See Q224815 - The Role of the Inter-Site Topology Generator.