There's something I don't get - I am always under the impression that the more transistors we pack in, the more energy it consumes and the hotter it gets (assuming we haven't shrunk the die). However, the Apple A8 has around 3 billion transistors while the Intel Haswell has half the transistor count, yet the A8 is able to run cool and takes much less energy to compute.
Can anyone explain the difference?
It is the clock frequency, i.e. frequency of the switching, and the number of transistors actually being switched at the same time that consume the power, and consequently, generate the heat, and not the number of transistors.
For example there could be a large amount of transistors in a area of the die that aren't being used, and so, if they are in the off (closed) state, then they will not draw any current, so less energy and less heat.
However, if some active area is switching at a higher clock frequency, then (on average) they are open for more of the time, and so draw more current, thus energy and heat.
Hope that helps.
