We've noticed that on bootup, there are CHECKDBs being run against all databases on the instance being restarted. At first I assumed it was standard procedure and did some research. I found a couple of posts stating that this happenswhen the server goes down without allowing the dabases to properly close.
Although that makes good sense, why are these CHECKDBs only takeing a couple of minutes to spin through? Even PHYICALONLY should take an hour or more to complete.
SQL Server is not really running a CHECKDB at startup. Michael Campbell does a good job of explaining what you're seeing: Why is SQL Server running DBCC CHECKDB against my databases at Server Startup?