Excuse my 'tism, but I just can't seem to get perfectly smooth frame rate in RetroArch on Android. I mean in systems like SNES that are easy to emulate. I read somewhere that it's almost impossible to get perfectly smooth picture on Android in RA. Played with vsync, hard sync to GPU, didn't really do exactly what I wanted. Threaded video did seem to do something, though it still didn't feel perfectly smooth.
I have the refresh rate set to exactly 60hz though, if this matters.