- Everything in Jelly Bean feels fast, fluid, and smooth. Moving between home screens and switching between apps is effortless, like turning the pages of a book.
- Jelly Bean improves performance throughout the system, including faster orientation changes, quicker switching between recent apps, and smoother and more consistent rendering across the system through vsync and triple buffering.
- Jelly Bean has more reactive and uniform touch responses, and makes your Android device even more responsive by boosting your device’s CPU instantly when you touch the screen, and turns it down when you don’t need it to improve battery life.
Lots more in source