Hi Guys.
So, i have a rather strange issue with Retroarch (and some other Emulators as well) running on an Jailbroken iPad Air 2, iOS 8.4 When running some more demanding games, the framerate sometimes drops from a otherwise rock-solid 60 fps to around 58-59 fps. At that point, there is noticeable visual choppiness and some audio-stutter. I’ve been looking into that issue for well over a year now, and noticed that it only seems to occur when the uncapped farmerate, of a game, drops below around 200 fps. Any game that is able to run above 200, sync’s to steady 60 fps.
I also tested it on my older original iPad Air. That one run’s all the problematic games at steady 60 fps, without ever skipping a frame. No issue’s at all here. When Benchmarking both devices with uncapped framerate, though, the Air 2 performs as expected. With higher framerate’s across the board. I tried everything i can think of, to get rid of that issue. sadly, to no avail. Tested all Retroarch versions (stable and nightly), possible configs etc. Happens on iOS 8.0 up to 8.4 (All jailbroken) Set up the Air 2 from scratch a bunch of times as well.
Strangely, all other app’s and game’s seem to run fine and smooth. Only exception being, some other Emulators. Which seem to have the same issue. (Snes 9X EX+, for example) A good example game, to test this, would be Yoshi’s Island for SNES. On the Titel screen with the rotating Worldmap, it always hang’s around 58-59 fps and is a bit jerky. (using the Snes9x 1.53 core for this one)
Any advice would be much appreciated. Perhaps someone with an Air 2 still on 8.x could verify this issue. That would at least rule out a (albeit unlikely) hardware problem. Thanks for your time and Sorry for the Wall of text, on this rather complex Problem.