Galaxy S4 : Retard au dévérouillage

Problem: Lag or stutter

Many people have found that the S4 stutters out of the box. There are reports of stuttering on entering and exiting apps, some lag on unlocking, and also lag when pressing the Home button. You can reasonably expect a smartphone this powerful to be as smooth as silk. If it isn’t then you can try the following:

Possible solutions:

Go to Settings > Developer options and scroll down. Try changing Window animation scale, Transition animation scale, and Animator duration scale to Animation is off. If you don’t see Developer options then you can unlock it by going to Settings > More > About device and tapping the Build number several times (you should get a pop-up message when developer options is unlocked).
Go to Settings >My device > Lock screen and then tap Unlock effect and change it to None.
Fire up S-Voice and go into Settings and then uncheck the box next to Open via the home key. Be aware that this will disable the double tap activation for S-Voice, but it will also eliminate the Home button lag.