Correct time drift throughout entire Windows domain

Upping the tolerance would probably work, however you would probably want to allow more than 90 minutes. I would wait at least a day.

Here are some additional considerations:

• Disable any hardware clock synchronization for domain controllers that are virtuals/guests.

• Configure the PDC Emulator role domain controller to synchronize with an external time source.

• Configure the registry values using group policy for the following settings to be 48 hours (MaxNegPhaseCorrection, MaxPosPhaseCorrection decimal: 172800, hex: 0x0002A300)

• Configure all other domain controllers, member servers, and workstations to use the domain hierarchy for time synchronization (NT5DS).

• If you do not use the PDC Emulator role domain controller for the external time synchronization, it should not be a domain controller with any of the other infrastructure master roles.

Configuring a time source for the forest
http://technet.microsoft.com/en-us/library/cc784800%28v=ws.10%29.aspx

How the Windows Time Service Works
http://technet.microsoft.com/en-en/library/cc773013%28v=ws.10%29.aspx

AD DS: The value of MaxPosPhaseCorrection on this domain controller should be equal to 48 hours
http://technet.microsoft.com/en-us/library/dd723684%28v=ws.10%29.aspx