SDTM checks versus SDTM plus Define.xml checks

When a user runs OpenCDISC Validator on SDTM data is the set of SDTM checks the same set of SDTM checks used when OpenCDISC Validator runs using SDTM data plus the define.xml?  

Is the first option (SDTM only) a subset of the checks of the second option (SDTM + define)?  OR are there differences in the suite of checks that are used by OpenCDISC Validator for these 2 options?  We want to be sure we aren't missing any checks when running option 1 vs option 2.

I had assumed it was the same for both runs but would like to verify this with you.  Thanks!