Stutter and tearing demo. Five ways it goes wrong.
When motion looks bad it helps to know which fault it is, because each has a different cause. This draws all five on purpose: smooth, microstutter, stutter, the halving that vertical sync does, and tearing. Once you have seen each, you can name what your game is doing.
One check
- Stutter and tearing
One check after another, with your progress along the top and a plain verdict on each. Nothing you show the camera or say into the microphone leaves this page.
What it measures
Measured here, not assumed.
- Microstutter
- One frame in eight lands a step short. Barely visible, felt as a roughness; usually two frames delivered too close together.
- Stutter and halving
- Frames in bursts, or every frame shown twice. A busy machine, a slow drive, or vertical sync falling to half rate.
- Tearing
- Two frames on screen at once, split across a line. Vertical sync off and the frame rate not matching the refresh.
If it fails
The usual failures, and what fixes each.
- Your game tears
- Turn on vertical sync, or better, variable refresh rate (G-Sync, FreeSync) if the monitor has it, with the frame rate capped just under the refresh rate.
- Your game halves
- Vertical sync without variable refresh drops to half rate when a frame is late. Use variable refresh, or a frame cap the machine can hold.
- Your game stutters
- Look for what is busy: a background program, a full drive, a driver. The frame pacing test shows whether the machine can deliver even frames at all.
Where a browser stops
What it cannot tell you.
- These are drawn faults, not measured ones. The frame pacing test measures what your machine actually delivers.
- A game's stutter has causes a page cannot see: shader compilation, loading, a background process. The pictures help you name it; the fix is in the game or the system.
- Variable refresh rate removes tearing and halving; this shows what they look like without it.
Privacy
Nothing leaves this page.
The camera and microphone are read on this page and stopped as soon as they have been measured. The clip you can play back lives in the browser's memory and is discarded when you leave. The location check discards the position. The internet test sends random bytes to this site and nothing else. The result is stored nowhere unless you ask for it by email, and then only the fact that an email was sent is kept.
Questions
Stutter and tearing demo, answered
- What is the difference between stutter and tearing?
- Stutter is time: frames arrive unevenly, so motion jumps. Tearing is space: two frames share the screen, split by a line. The demonstration shows each.
- What is microstutter?
- Small, frequent unevenness in frame delivery, often two frames bunched together. It looks like a roughness rather than a jump, and it is common with multiple graphics cards or badly paced frame caps.
- Does variable refresh rate fix stutter?
- It fixes the halving and the tearing, because the screen waits for each frame. It cannot fix frames that are late; that is the machine, and the frame pacing test shows it.
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