Speculative execution

Speculative execution is a way that computers can guess at what they think you might want them to do next, so they can get started right away and work faster. Think of it like this: if you were walking home, your computer could guess which route you would take, and start on that route, rather than waiting for you to decide which way to go. If it guesses right, then your computer can finish its work very quickly, and you might not even notice that it was thinking ahead. However, if it guesses wrong, then it has to go back and start over.