Xbox One June Update is out for beta testers, and many are reporting improved game load times using external hard drives.
Xbox One External Hard Drive increases game load times: Neogaf
Xbox One’s External Storage Can Actually Improve Games’ Loading Times Considerably: Dualshockers
Xbox One June update adds external storage, real player names: CVG
“Easily Increase Games Capacity with External Storage Support: It couldn’t be easier to increase your storage capacity of games and apps with the external storage support features we’re bringing in June. Your Xbox One system will soon support up to two external hard drives at once. Simply plug in your 256 GB or larger USB 3.0 external hard drive and once formatted, copy and move games, apps and game add-ons to increase your storage capacity at home. This is also a great way to take your content to a friend’s house and get straight into a game directly from an external drive. You’ll need to sign in to Xbox Live if you’ve purchased your content digitally or insert a disc to verify your game ownership when you take your content on the road. The great benefit here is there’s no need to wait to re-download your game and all the DLC. With external storage support in June, you can also choose to copy full games and all of the associated content in one easy step.”