@lee.pellegrin In full AutoCAD, SAVE lets you create a second DWG file without ever leaving the file you are in. Nothing more. Your current file remains unsaved. QSAVE simply "saves" your current open file. Nothing more.
In the LT versions of AutoCAD, both behave like QSAVE. HELP in both programs explain it all if you need to do a deep dive.
The way I remember the SAVE feature is it’s like making a copy of the current drawing when you give it a different name. Whereas SAVEAS creates a copy and ends up in that dwg. QSAVE is the fastest because no dialog appears for user input and current dwg is saved with a backup file created
