Journey
Banned
I don't think it's rendering at 90fps, it's the game logic that's 90hz.
To my understanding, KI has to perform at 90hz internally in order to send actual frame data. There would be no point in sending fake/duplicate frames, but I could be wrong.
While the game is still outputting to monitors at 60 fps, the game’s engine renders the graphics at 90 fps and then performs a “rollback” to 60 fps. This allows Killer Instinct to read controller input at a much higher rate, which makes gameplay feel smoother whether in single-player or multiplayer. The latter is the key part, combined with the netcode to enable online play.