Make WinXP’s NTP client poll more frequently

My laptop’s clock seems to get out of sync and fall behind quite often. I suspect it’s because the clock frequency keeps changing thanks to the power-saving SpeedStep stuff. However, it’s irritating that my clock is always wrong–especially when Windows XP has a built-in NTP client! Of course, the default is to poll once a week (!) … and the “Date and Time Properties” dialog doesn’t allow you to configure how often to poll.

Luckily, it is configurable through manual modification of a Windows registry value. It’s in the registry hive, here:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpClient

The value is SpecialPollInterval which is a DWORD number of seconds that is set to 604800 (one week) by default. I’ve ratcheted it down to 3600 (one hour) to minimize the drift of my clock but not putting undue stress on my local NTP server.

Once you’ve made the change, you’ll need to restart the Windows Time service in order for it to pick up the new interval. From a Command Prompt:

C:...> net stop "Windows Time"
The Windows Time service is stopping.
The Windows Time service was stopped successfully.

C:...> net start "Windows Time"
The Windows Time service is starting.
The Windows Time service was started successfully.

That’s it. You’ll want to click the “Update Now” button in the “Internet Time” tab under “Date and Time Properties” to force a NTP sync. and update the “Next synchronization:” date with your new poll interval.

I hope this tidbit is useful to anyone else looking to adjust the polling frequency of their Windows NTP client. I know this has certainly bothered me for a long time before I finally figured it out.

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8 Responses to “Make WinXP’s NTP client poll more frequently”

  1. Ash says:

    Just brilliant! the battry backup on the motherboard is dying and this is just works fine! Better than installing extra software. Thanks

  2. Dossy says:

    Ash: I’m glad it was helpful to you! Thanks for stopping by.

  3. Anonymous says:

    Thank you for this blog entry! It has been extremely bothersome with the clock drifting and Windows NTP not polling often. Micrsoft should really make these parameters tunable via the control panel.

  4. Philip says:

    Unfortunately time.windows.com doesn’t seem to be up to date with the daylight savings dates we have in NZ. Any suggestions for how to get around this? Daylight savings time here now starts on the last weekend of September (previously the second weekend of October). Any suggestions on how to fix this? Why does the time server not identify this correctly?

  5. Philip: This isn’t (necessarily) an issue with time.windows.com or any other NTP server. The Network Time Protocol (NTP) distributes time in UTC/GMT. It is up to the operating system running on the NTP clients (i.e., your computer) to know what timezone it is in, and compute the local time accordingly.

    What OS are you running? Presumably there should be a patch or update to your OS that should correct the change for DST in your time zone.

  6. Philip says:

    Thanks Dossy, you were right. I am running Windows XP and for some reason automatic updates are not running (the bane of my life). Anyway I used a utility called TZEdit to edit the daylight savings start and end dates manually. Then I had to tick the “automatically apply daylight savings” box off, hit apply, then tick it on again and apply. And voila the time adjust correctly. Thanks for pointing me in the right direction.

  7. Philip: Glad you could get it sorted out! Thanks for letting us all know what your solution was – hopefully it can help someone else, as well.

  8. robert schmitt says:

    this has saved me tons of time to fix our source code syncing problem

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