Frame pacing
Delivering frames at even time intervals — uneven frame times bother the eye more than a lower but steady frame rate.
Raw frame rate hides a subtler truth: 60 frames per second where every third frame arrives late reads as stuttery, while a steady 50 feels silky. Frame pacing is about the variance in the time between frames, not the average. Microstutter — short, recurring hitches — is almost always bad pacing rather than too few frames.
The causes live in present timing to the display, in the vsync logic, and in how simulation and rendering are synced. Google's Swappy library for Android and equivalent present queues on PC exist precisely to even out delivery.