One other thing this deck doesn't go into but has a huge impact (for games at least) is frame rate. Higher frame rates require the GPU to get the work done in a shorter amount of time and make it less likely that the GPU will be able to switch to an idle power save state.
A good example of this in action is the game Threes. The developers implemented a "power save" feature in the game which simply cuts the frame rate in half[0], causing the app to consume noticeably less battery.