Setting you frames per seconds very high on a screen transition or animation might seem like a great idea that will make your UI look better. However if your target system can't keep pace with the requested frame rate the Storyboard Engine will simply drop the frames that is can't display and do extra work to achieve a lower fps that may look even worse. Usually a frames per second of 14 will look good on simple animations. The results can vary depending on what is being animated how long it is being animated for and what the content it is being overlaid to is composed of so the best plan is to evaluate your design on the target hardware and tune the settings appropriately.