Should I convert XML to JSON for performance reasons?

I am currently storing my settings using the Visual Studio integrated Settings-Management-System, which uses XML. But in this article [http://ift.tt/Jj02IQ ] I read that "the fastest XML is ~50x slower than the slowest JSON". So it could be that it would be more perfomant when you convert given XML-Data to JSON and then deserialize it. I did not any find any tests and do not know how I could test it. So would this way be more perfomant and from which amount of data is it (how much) profitable? The JSON-Framework I mean is fastJSON, the probably fastest JSON-Framework in C#.