Regular Mode is for general duplicate scanning, especially when you are just interested in comparing exact file contents or other attributes such as filename, date and size.
Same Content option
This option will find files with exactly the same content inside, regardless of name or date.
Note: For advanced users, the method using for comparing exact files can be changed in the Options screen.
Use this option if you want to ignore the content of the file, and instead compare by criteria such as file name, size or date. You must select an additional criteria when using this option.