digitalsoapbox What kind of numbers are you guys talking about? In Crystal Brawl, on player input (so characters start moving) it drops maybe 2-5fps. I figure this is normal due to the extra physics and animations kicking in. No particularly noticeable hitch to me. Are you guys seeing much greater frame drops?
It occurs where there are no physics at all, where there are no animations, and with no objects responding to player input. As soon as player input occurs, every second or so, even after input has stopped, there is an obvious hitch.
Spawn a small sprite with no animations (just a green square, for example), behaviors, or shaders off-screen to the right every second or so, and move them across screen to the left (self.X = self.X - 100*dt), deleting them when X position < 0 + self.Width/2. Make sure the Gamepad object is in the project. As soon as there is player input, repeated hitching will start. With so little going on, it's had to justify any framerate dip at all, and because it only happens after player input, it's unlikely that it's connected to anything going on in-game outside of the input.
The issue, as I said earlier, is also noticeable on desktop Edge, though it takes a heavier load to become more pronounced that I'm fairly certain is not connected to anything that has to do with physics. In Sombrero, which is much heavier than the above example, all physics run fine and there are no hitches in framerate until player input starts (though performance is overall much lower than in NW.js).
UPDATE 11/13/2017: The latest Dev Beta OS released to Devkits over the weekend reduces the issue somewhat, but it's still there. Seems Microsoft is working on the gamepad issue.