3/4 and 6/8 are different because of the beats each note gets assigned. One time signature would move slower than the other due to the same notes getting different beats.
Explanation:
3/4 gets 3 beats per measure, with each quarter note equaling one beat, whereas 6/8 has 6 beats per measure, where each eighth note gets one beat. Though the notes look the same on paper, a quarter note would be twice as long in 6/8 than it is in 3/4, equaling two beats instead of one. The reason you would choose one over the other would be the pace you would like the song to go. If you take the same piece of music, but put one in 3/4 and the other in 6/8, the one in 3/4 would finish faster than the one in 6/8.
