The fan is blowing on this brand-new MacBook Air with Retina Display. It’s a familiar sound: a computer trying to cool down a processor that’s being overtaxed by one of the eight or so apps I have running. (In this case, it’s TweetDeck going rogue.) But it’s also a sound you don’t hear on more futuristic computers like the iPad, the Surface Pro, or even the Pixelbook. Still, fan or not, the computer is handling everything I’m doing just fine, and a quick restart of the app quiets it down.