Were you worried that Microsoft would leave the Surface Book untouched during its Windows 10 event? You can set your mind at ease. Microsoft has unveiled the Surface Book i7, a refresh that focuses on pure power. The name is a giveaway as to the processor (surprise, there's a Core i7), but you also get twice the graphics performance -- the company added a second fan and otherwise redesigned the thermals to allow for faster GeForce GTX 965M video without cooking the inside. There's also a larger battery that promises up to 16 hours of battery life in laptop mode (no word on the tablet mode yet).