Have you tried clearing the cache partition?
I have an app called Startup Manager for killing the apps that are starting when the phone boots. I'm not sure if is good. Do you know of any better?You should check to see if you have apps running in the background. Another app won't magically make your phone faster so easily.
Wizzrah, Android Central Ambassador | Sent from my AT&T One XL running Karbon Kat. \(^~^)/