Remember when Microsoft said the Xbox One S doesn't have a GPU and CPU boost and that it plays games identically the same as the normal Xbox One? Yeah, they totally lied. The Xbox One S is not only faster, but it can boost in-game frame rates by 11% and beyond.
Microsoft's new $299 Xbox One S has some hidden powers. Not only does it upscale 1080p games to 4K resolution, play 4K UHD Blu-rays and supports High Dynamic Range, the new console is equipped with tweaked hardware that delivers a consistent and noticeable frame rate bump.
According to Digital Foundry's testing, the Xbox One S offers overall improved frame rate and power efficiency performance over the original Xbox One. The S model's performance jump comes from its new internal hardware, which is comprised of a new shrunken 16nm FinFET semi-custom AMD SoC which houses an overclocked GPU (boosted to 914MHz from the vanilla Xbox's 853MHz), improved ESRAM bandwidth (219GB/s versus the vanilla's 204GB/s), and a smidgen of 0.9 extra teraflops performance. Remember that the original Xbox One featured a 28nm AMD APU, so the Xbox One S enjoys a 33% die shrink that translates into some serious power efficiency. The CPU, however, hasn't been boosted and remains at 1.75 GHz.
"The Xbox One S is like the console equivalent to a factory overclocked graphics card. The same, but a bit better," said Digital Foundry's Richard Ledbetter.
How does this hardware actually impact game performance? DF tested multiple Xbox One games on the Xbox One S and saw a consistent frame rate increase on many games tested. In fact, some games like Project Cars saw an 11% FPS boost on the Xbox One S, and Leadbetter notes that the new Xbox can boost frame rates by up to 9 FPS. The smaller Xbox also saw less tearing on games like Arkham Knight.
At the same time, however, there were some games that saw no performance boosts. Fallout 4 was the same on Xbox One S and original Xbox One, with absolutely zero boosts in any capacity--so it just depends on the game.

When Digital Foundry contacted Microsoft with its findings, Redmond finally admitted that the Xbox One S is actually better than the old model:
"Some games, those that utilize dynamic resolution and/or unlocked frame rates may see a very minor performance increase. Our testing internally has shown this to be pretty minor and is only measurable on certain games. So we didn't want to make it a selling point for the new console."
