Why average FPS masks frame pacing problems
A system averaging 60 FPS might deliver 16ms frames most of the time but occasionally spike to 50ms when a background process runs. The average hides these spikes. A player experiences the longest frame as a stutter, not the average. Frame time graphs show every frame in sequence, exposing the worst-case experience.
An inconsistent 60 FPS (45ms then 16ms then 18ms) feels worse than a consistent 50 FPS because the brain detects variation as jank. Frame time graphs make this visible and comparable across different systems or settings.
Measuring what players actually feel
The time between pixels hitting the screen is what determines perceived smoothness. A frame that takes 20ms feels smoother than one that takes 30ms, regardless of how many frames per second the system claims to deliver. Frame time analysis separates the outliers, showing which settings or hardware combinations create the smoothest experience for the player.