Hi and Welcome!
any speed above 16x is "overspeeding", i.e. writing at a higher speed than the given media is certified for.
This overspeeding works only for a few high quality blank media, either from Verbatim or Taiyo Yuden.
It is good for big marketing figures (and perhaps for the ego), but in real world application, such an overspeed is not recommended. Most users prefer 8x or 12x