Problems · Under load
Why does my game stutter even at high fps?
Because the average frame rate is not what you see; the gap between frames is. Sixty frames delivered every 16.7 milliseconds look smooth. The same sixty with some late and some bunched look like stutter at the same average, and a frame counter cannot tell the two apart.
The frame pacing test on this site times twenty seconds of frames, draws each as it lands, counts the ones that missed their refresh and the gaps of three refreshes or more, and reports the late share, the hitches, the 99th percentile interval and the 1% low. That separates a machine that can deliver even frames from one that cannot, before you touch a game setting.
First, notice when it happens
The causes, ranked
1. Frames capped or synced to the wrong rate
most commonHow to confirm it
Vertical sync on without variable refresh, so any late frame drops the rate to half; or a frame cap set above what the machine can hold.
The fix
Use variable refresh (G-Sync, FreeSync) with a frame cap two or three below the refresh rate; without it, cap at a rate the machine holds every frame.
2. Something else on the machine
most commonHow to confirm it
The frame pacing test reads uneven with the game closed: overlays, recording tools, browser tabs, RGB software, a background update.
The fix
Close them and run the test again; an even result means the machine can pace frames and the game is the culprit.
3. Two monitors at different refresh rates
commonHow to confirm it
The refresh rate test reports two cadences, or stutter appears only with the second monitor connected and a video playing on it.
The fix
Match the rates, or move the game to the main monitor and close video on the other while playing.
4. Heat, over minutes
commonHow to confirm it
Smooth for the first minutes, then uneven; the stress test on this site shows the machine losing speed over its run.
The fix
Cooling first: vents, a hard surface, then cleaning. Frame pacing recovers as the chip stops throttling.
5. Shader compilation and asset streaming
occasionalHow to confirm it
Hitches in new areas of a game, then smooth on revisit; a drive near full or a slow one.
The fix
Let the game precompile shaders where offered, free space on the drive, and move the game to the faster drive.
Reading frame pacing results
The frame pacing test asks the browser for a frame at every refresh and records the time between the frames it actually got. A smooth result is a tight band of intervals around one refresh period. Stutter shows as intervals that are double or more, scattered through the run; bunching shows as short and long intervals alternating. The average frame rate can be identical in all three cases.
Use it to rule things in and out. If the browser test is smooth while a game stutters, the cause is likely in the game: shader compilation, streaming or its frame limiter. If the browser test stutters too, look at the system: a second monitor at a different rate, background work, or power settings. Then run a longer test to see whether stutter grows as the machine warms.
Measure it instead of guessing
The frame pacing test times twenty seconds of the browser's own frames and reports the late share, the hitches, the 99th percentile interval and the 1% low, so you know whether the machine can pace frames before blaming the game. The stress test shows whether the machine holds its speed over minutes.
What software cannot tell you here
- A page measures the browser's frames, not a game's. An even result means the machine can deliver even frames; the game adds its own work on top.
- It cannot see shader compilation, asset loading or a specific driver; it can rule the machine in or out.
Asked, in people’s own words
- What is frame pacing?
- How evenly frames arrive. Two machines at 100 fps can feel completely different if one delivers a frame every 10 ms and the other delivers them in bunches.
- What is microstutter?
- Small, frequent unevenness, often two frames bunched together, felt as roughness rather than a jump. The stutter and tearing demonstration shows what it looks like.
- Does variable refresh rate fix stutter?
- It fixes the halving and tearing that vertical sync causes, because the screen waits for each frame. It cannot fix frames that are late; that is the machine.
- Does a higher refresh rate monitor hide stutter?
- It shortens each frame, so a single late frame is a smaller gap. It does not fix uneven delivery, and on a fast screen uneven pacing can be easier to notice because the smooth frames around it are so smooth.