Any gif that claims to be showing 60fps is simply untrue due to the fact that no web browser out there right now supports displaying gifs higher than 50fps. If you try to set your frame rate any higher than what the browser supports (or if you set the frame delay to zero) then most browsers will default to a playback of 10fps (over 5 times slower than you probably intended).

FROM: https://sebsauvage.net/links/?ZYOVJA

À savoir : les navigateurs ne supportent pas les GIF animés à plus de 50 images par seconde (50 fps).