The title pretty much explains it all. I am using a little framerate GUI counter on-screen to get a basic idea of the framerate and it seems to be capped at 30 FPS even when there's nothing really happening. My game is still in a very early prototype, so there isn't much that should be affecting performance.
I seem to recall reading somewhere on the site that frametime on iOS devices is locked to multiples of 60Hz (.0166 sec), so does that mean the framerate is locked to either 60, 30, or 20 FPS?
This isn’t a direct answer, but I hope it helps to put frame rate in perspective:
Film has been 24 frames per second for a long time. US TV broadcasts 29.98, PAL, used outside the US is usually 25. Digital (generally 720p or 1080p) can be either 24 or 25 FPS, though I find 24 is becoming the standard since it matches film.
The human eye is fooled by as little as 12 frames per-second, which is what the old cartoons would use for just this reason. They could draw less frames and still achieve smooth motion.
When dealing in 3D (stereoscopic), generally the frame rate is doubled to get alternating frames for each eye (depends on the viewing system).
As long as you are over 24 FPS you shouldn’t have anything to worry about. Anything over 30 is arguably a waste of processing power. A lot of people find super high frame rates creepy in live action. It can be nice for games but again, this is of diminishing value to quality when compared to processing (and I hear battery) power.