Frame Time Variance & 99th Percentile Stutter Calculator
Convert Average FPS and 1% Lows into milliseconds of frame pacing jitter, measure micro-stutter severity, and find your optimal VRR cap.
G-Sync / FreeSync + V-Sync Formula
For your 240Hz monitor, set your in-game limiter to 237 FPS (Refresh Rate minus 3). Keep G-Sync ON and V-Sync ON in the NVIDIA Control Panel to prevent input lag surges caused by the GPU hitting the refresh ceiling.
Frequently Asked Questions
Why does 200 FPS still feel jittery or stuttery?
Average FPS only tells half the story. If your game outputs 200 frames in one second, but 50 of those frames take 16.6ms to render while the rest take 2ms, your frame delivery is uneven. Uneven frame pacing causes visible hitching and camera stutter even when your FPS counter reads a high number.
What is 1% Low FPS and why is it more important than Average FPS?
1% Low FPS represents the average of the slowest 1% of frames rendered during a benchmark (the 99th percentile frame times). When engaging in gunfights, smoke grenades, or fast camera turns, 1% lows reveal how hard the engine stutters during critical moments.
Why do competitive players cap FPS at -3 below refresh rate (e.g. 237 FPS on 240Hz)?
When pairing G-Sync / FreeSync Variable Refresh Rate (VRR) with V-Sync, capping FPS 3 frames below your monitor's maximum refresh rate (e.g., 141 on 144Hz, 237 on 240Hz, 355 on 360Hz) prevents the GPU from hitting the monitor ceiling where standard high-latency V-Sync buffer backpressure kicks in, giving zero screen tearing with minimal input lag.
What is the difference between an in-game FPS cap and RTSS (RivaTuner)?
In-game frame limiters operate earlier in the render pipeline (CPU simulation stage), producing lower input latency. RivaTuner Statistics Server (RTSS) caps frames at the presentation queue, producing mathematically flawless flat frame times (perfect frametime pacing) at the cost of approximately 1 frame of input lag.