If I want to order a BTO Macbook Pro, and can choose whichever custom configuration I want, which processor speed should I choose if I want to optimize for least heat and best battery life? eg: does the default processor run cooler because it's slower or hotter because it has to work harder? does the fastest i7 option run cooler because it hardly ever has to go to turbo? does the default processor use less energy because it has a slower clock speed, or more because it has to turbo more? You get the idea of what my confusion is. thank you in advance.