That's my bad, you are correct! My assumption was that frame delay exploits the fact that CPU are way faster than original hardware (hence you can defer comput

That's my bad, you are correct! My assumption was that frame delay exploits the fact that CPU are way faster than original hardware (hence you can defer computation later since it will take less anyway) and since the most common trick to increase battery life is to slow down the CPU, eating away at your extra budget, you would want frame delay disabled, but that is definitely not correct. If anything, Automatic Frame Delay would probably help letting you tune in CPU speeds without worrying too much about adjusting the Frame Delay as well.