I'm pretty sure this whole intelligence is merely thinking faster idea is non sense. From my own personal experience, I think quite slowly, I'm bad at mental arithmetic, but I have a very high IQ. Look at IQ tests, our best measure for intelligence: getting the questions right is not about speed, it's about insight. The harder questions do not require more time, it is not simply a matter of enumerating through the different options. One has to "see" the patterns and then apply the rules.