Windows Time

I've noticed that my Media Center PC's recordings haven't quite been aligned with the shows' time slots recently, and tonight I overcame laziness and actually looked into it just a bit. The PC's clock was off by just over a minute, which is about how late my recordings have been starting.

I've used apps like Atomic Clock Sync in the past, as a replacement/addition to the built-in Internet time synchronization in XP/2003. I usually prefer to keep things simple and just use built-in Windows functionality for these types of things, unless a third-party app really adds some value or features. In this case, the Windows time sync works, but I want it to check more often than the default setting (which appears to be 7 days on XP Pro, and 1 day on XP MCE). A minute or so isn't usually a big deal for most desktop applications, but for some (like media centers and most servers) it can make a big difference.

You can change the synchronization frequency pretty easily with a quick registry tweak:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpClient
Modify or add the DWORD named "SpecialPollInterval" and set the decimal value to the desired interval, in seconds (86400 = once per day; 3600 = once per hour). Then restart the W32Time service. You can verify the change on the Internet Time tab of the Date and Time Properties control panel window.

I've set mine to 7200 (2 hours), so hopefully my recordings will start and stop at the correct times now.