You might wonder about IQ: IQ or "g" is literally the measure of how fast you can recognize and employ new patterns, and therefore how fast you'll master new micro-skills. Kids with higher IQs will do better under time-constraint. But given as much time as needed, and assuming mastery of previous subjects, IQ is irrelevant.

Everyone can recognize a pattern or get a lateral thinking puzzle eventually. Adding the time-constraint splits the world into people who can recognize patterns quickly enough to employ that pattern-recognition in the course of their every-day life, and those who can't: thus, IQ. Without the time constraint, an IQ test wouldn't really measure anything at all.

IQ is believed to relate to intelligence because the ability to see patterns sufficiently quickly gives you a kind of "intuition" for new subjects. It's like a lubrication against friction: without it, new subjects will be "at rest" in your mind, and you'll have to give them a push to get your understanding of them going. With it, they'll just slide down the funnel right into your brain.