well the GPS saver only takes samples and isn't on the entire time like it would be if its off. In that sense if you are on a path and has twists and turns it wont see that and you'll need to put it on the full GPS. Only reason why gps is there with the runs, biking, and such is to see how fast your going at the path your going afterwards and make you push more. but that's what i think it does. but i don't use GPS because i honestly don't care how fast i'm going on the path i've traveled 1000 times unless i'm training for a marathon best record or something. i see it if there is a hill i'm going to be going slower and faster over the hill because you're still compensating for the incline and going faster down because its down lol