I am completely new to Mac but isn't the new Mavericks OS suppose to decrease power usage too? I thought that was one of the big deals of the new OS.
I should, but I we'll have to wait for the actual tests. App Nap is probably the biggest improvement, but it won't help maximum battery life. It will only help you if you keep prefer keeping apps in the background to closing them. The various App improvements will depend on how they were already performing compared to their competition. For instance, I have my doubts that iTunes is a very power efficient app. I don't know about Safari, but at least it should make long battery life more easily achievable for most Mac users. Timer Coalescing is already being used by Windows 7 and 8 without any astonishing results. I've been looking around at some forums for beta results. The impression I have is that will be some improvement, but it's hard to say without someone taking their time to set up rigorous test conditions.