How to Fix Physics That Behaves Differently on Different Hardware

Physics differing across hardware is frame-rate dependence or floating-point divergence. Fixing the timestep helps most. Here is how.

How to fix it

1. Use a fixed timestep

Step physics at a fixed rate independent of frame rate so behavior is the same whether a machine runs at 30 or 144. Variable-step physics produces different results on different hardware.

2. Reduce floating-point sensitivity

Floating-point results can differ subtly across CPUs and compilers. Avoid logic that depends on exact equality, add tolerances, and do not let tiny differences cascade into divergent outcomes.

3. Use deterministic math where it matters

For lockstep multiplayer or replays that must match exactly across machines, use fixed-point or a deterministic math library, since standard floating point cannot guarantee identical results everywhere.

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.