In a live stream interview with PlayStation during E3 2016, Hiroaki Kato talked about the best way to take advantage of the speed modes in the upcoming, Final Fantasy XII: The Zodiac Age. The producer of the project first stated that the game is famous of having vast fields to move across, which takes up a lot of time in normal speed. As a result, a 4x speed mode was implemented.
With that said, the development team found that speeding up the game at four times the original made it harder to move in more crowded areas, including cities and dungeons. In situations like these, the producer suggests that players should use the 2x speed mode instead.
The turbo speed options have been implemented in many of the other recent re-releases of the series, including Final Fantasy VII, Final Fantasy VIII, Final Fantasy IX, Final Fantasy X and Final Fantasy X-2.
For the uninformed, Final Fantasy XII: The Zodiac Age is a remastered version of the original PlayStation 2 title. The PS4 version comes with improved graphics, rearranged soundtrack (although the original OST will also be available) in addition to having all of the extra content from the previous Japan-only International Zodiac Job System Edition.
You can preorder Final Fantasy XII: The Zodiac Age, which is coming out in 2017 for the PS4, with this link on Amazon.