When enabled, the mode drops your game's resolution and switches the graphics settings to "medium." If you care more about beauty than speed, you can hike the graphics up to "high" for 60 fps gameplay or to epic, which looks amazing but only runs at 30 fps on the iPad Pro.
For comparison, Fornite plays at 60 fps on the Xbox One and PlayStation 4. Other mobile systems, like the Nintendo Switch, only get up to 30 fps, which makes the 120 fps mode on the iPad Pro all the more impressive.
The iPad Pro is such a great fit for these high frame rates because the tablet's Retina display features ProMotion, a technology that enables refresh rates of up to 120Hz.
What does all that mean? The bottom line is that Fortnite will look incredibly smooth on the iPad Pro. So smooth that you might even have an upper hand when you're building a massive fortress or trying to snipe someone who is bunny-hopping across Salty Springs.
We haven't gotten a chance to test the new 120 fps mode yet but The Verge's Sam Byford says "the difference is noticeable," even though the frame rates drop into the 100s and 90s.
So the next time you get downed by an enemy in Fortnite, just know that they might have been playing on a tablet.