>Hi All. Can anyone confirm if switching off debug info when compiling a project affects execution speed (significantly) of the resultant exe file or only the file size?

To answer sort of "backwards," with the debugger 'ON' you get larger EXEs, of course. In my experience, the debugger 'ON' in Project has only a slight affect on performance, when the debugger is physically closed (I think this is what you are asking about). With debugger open, it has a large affect on performance, as you know.