From Phil Spencer's interview with gamesindustries.biz.
There are games that were written on Xbox One, and we continue to evangelize this tech of dynamic scaling - Halo 5's a good example - when Halo 5 runs it wants to max out at 1080p/60 frames per second or highest resolution/60 frames per second. As scenes get more complex, the vertical resolution will shrink... to keep the 60 frames per second. When that same game's running on Scorpio, because of the compute capability, it's effectively is going to run at its max resolution the whole time. And so you will see advantages like that when your Xbox One games are running on Scorpio. So that's why we continue to talk to developers about dynamic scaling because I think as compute capability goes up on the hardware, they kind of get it for free. Now, it's not going to make Halo 5 run with 4K pixels. The frame buffer is not a 4K frame buffer for the game. But it will run more solidly. And certain developers might go back and decide if they've built a 4K version for PC already for some of their games, they might go back and decide to enable a 4K version for the Scorpio Xbox when it launches.
Yes, another Phil Spencer thread but this is something I know myself and a couple other folk were wondering. Please lock it up if we're reached peaked Phil Spencer.