You cannot expect OnyX to make a positive difference in your application launch times. Optimization in the MacOS X sense means to prebind an application to its supporting frameworks. This is done automatically by the OS. In the early days of MacOS X it was sometimes not done. In that case, the app was bound when it was launched for the first time. In the best case scenario, you will waste more time running OnyX than you can ever hope to save by having used it.