Yes I saw it in my game. I think it's because a 90Hz display panel can only display a frame after 1/90th of a second, 1/45th (if it misses a frame), 1/30th, etc. If your game's internal framerate is 85Hz, the panel will only display a new frame every 1/90 or 1/45 of a second, making the FPS jump between the two.
I'm on Unity, but expect the same will apply. I struggled with the same thing for a while. From what I can tell this is due to VSync forced on through the SDK. It will lock the FPS to 90, if you get less that 90 fps it drops to 45 fps.If you are constantly jumping between FPS I would suggest you have something in your game that is causing you to drop below 90 FPS. To combat this I created a script to report the FPS to a canvas attached to my camera so it told me to FPS for where I was looking on the game. Turning on and off objects will often lead to finding the offending object(s). I got the the point of check lights, particles and shadows first as these were often the biggest offenders.Hope that helps a ltitleMike
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