What causes movement speed scaling with the render frame rate?

You apply movement in the per-frame render update without delta-time scaling, so more frames per second means more movement steps and a faster character.

How do I catch this when it only happens for some players?

Capture it automatically from the player's device with the full stack trace, the device and OS, the build, and a breadcrumb trail of what they did. That turns a vague complaint into a specific, reproducible issue you can fix without owning the hardware it happens on.

How to Fix Movement Speed Tied to Render Frame Rate Instead of the Physics Step

Quick answer: Either scale movement by delta time in the render update or perform physics-based movement in the fixed-timestep callback so speed is independent of frame rate.

A character that sprints faster on a 144 Hz monitor than a 60 Hz one has frame-rate-dependent movement. Decouple it from render rate. Here is how.

How to fix it

1. Move in the fixed step

For physics bodies, apply velocity and forces in the fixed-timestep callback (Unity FixedUpdate, Godot _physics_process) which runs at a constant rate regardless of render FPS.

2. Or scale by delta time

If you move in the render update, multiply every displacement by the frame's delta time. A fixed per-frame offset is the root cause of frame-rate-dependent speed.

3. Interpolate visuals

When physics runs at a fixed rate below the render rate, interpolate the visible transform between physics steps so motion looks smooth without coupling speed to the frame rate.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.

Ship the fix, watch the signature disappear from the next build. That's how you know it's really gone.