I am backing up SQL databases using DPM 2012 SP1. I have synchronization frequency set to 1 hour. Application recovery points set to Express Full backup at 8:00 PM everyday. Are the synchronizations that happen each hour differential backups? I am worried that if a database were to crash at 3:00 AM I would have to recover from 8:00 PM the night before.

Hi,

The Synchronization Job will initiate a SQL Log Backup, so take care that the Databases are configured with full Logging.

If the Database is in simple Mode, only a Backup at 8:00 PM will be created.

As mention, a synchronization is a Log Backup, so don't worry about loosing Data, DPM will provide you with recovery Point each hour, so you only will loose data back to the next full Hour.

But take care that your DB is in Recovery mode "full"