How set in Windows Server 2008 r2 interval to sync time with the PDC emulator?

In a Windows 2003 domain, I have 7 members servers that are Windows Server 2008 R2. I need to make it so that they sync time with the PDC emulator at least every 15 minutes or less if possible. Is this possible?

You can do this one of two ways:

Registry & 0x1 flag

As detailed here, if you set the 0x1 flag using w32tm, you can change SpecialPollInterval located in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpClient to however many seconds you want. For 15 minutes, it would be 900 seconds.

Scheduled Task

Alternatively, you can create a scheduled task that runs w32tm /resync every 15 minutes on the target computers. I strongly recommend this over the other option. It's much less complex and can easily be applied via GPO using the Scheduled Tasks Group Policy Preferences item.