To change the interval that Windows updates the time using the internet time servers via regedit, navigate to:
1. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services \W32Time\TimeProviders\NtpClient
2. Select "SpecialPollInterval"
3. Change decimal value from 604800 to a different value in seconds. i.e.: 172800 (2 Days) or 86400 (1 Day) and so on.

We don't recommend changing this unless you are on a broadband connection.