https://www.polygon.com/2018/7/5/17537164/xbox-one-faststart-july-update

The latest Xbox One system update began rolling out Thursday, and it brings a host of new features to the console, chief among them the ability to get into games more quickly.

FastStart, which Microsoft announced during its E3 2018 press briefing, lets players jump into a game after downloading a small portion of it. Here’s how the company described the feature in an Xbox Wire article: “FastStart works by identifying which files are needed to begin playing and prioritizes the download of those files first, enabling you to quickly jump into full-fidelity gameplay while the remainder of your title downloads in the background.”