Performance mode is a special execution mode of the program. In this mode, the generator does not write detailed diagnostics to log file. Also, it increases the interval between console window updates.
You can be sure that performance mode is on when {PM} stamp shown in the main window title.
To switch this mode on or off you can use command line switch -p or related option.
Depend on project and database system this mode may be faster that default from 20-30% to 300-500.