On Windows 2003 server/xp, the manual (NTP) mode of the windows time service CLIENT has a "SpecialPollInterval" which allows you to set a custom poll interval instead of what the OS decides.
I've been going through the MS docs on the registry settings for WTS here: http://technet.microsoft.com/en-us/library/cc773263(WS.10).aspx
It doesn't look like specialPollInterval works on NT5DS (domain hierarchy) mode. Is there something similar in this mode?
If not, how often will Windows poll for the correct time when the wts client is set domain hierarchy mode?
Seems it's controlled by MaxpollInterval and MinPollInterval, the minimum and maximum interval between polls respectively. The value in each is a time in log2 seconds (ie. 2^n, so specifying 5 is 2^5 = 32 seconds). The defaults for DCs are 6 (64 seconds) and 10 (1024 seconds) which seem sensible to me.
Both of these values can be found in HKLM\System\CurrentControlSet\Services\W32Time\Config.