What causes frame time spikes?

Occasional long frames among fast ones cause visible hitches even at a high average frame rate, and they come from periodic events — GC, loading, spawning, shader compiles — that are hard to spot without profiling.

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 Diagnose and Fix Frame Time Spikes

Quick answer: Capture a frame-time graph to find the spikes, profile a spike to identify its cause, and address each cause — GC, streaming, compilation, or heavy one-frame work.

Frame time spikes are periodic heavy frames. Profiling and addressing each cause fixes them. Here is how.

How to fix it

1. Capture a frame-time graph

Record frame times (not just average FPS) to see the spikes. A spiky graph with occasional long frames hitches even at a high average. The spikes, not the average, are what you target.

2. Profile a spike

Profile during a spike to see what the long frame spent time on — garbage collection, asset loading, spawning, shader compilation, or a heavy operation done in one frame. The profile names the cause.

3. Address each cause

Fix the identified cause: reduce allocations for GC spikes, async-load for streaming spikes, precompile for shader spikes, and spread heavy one-frame work across frames. Re-profile until the frame times are flat.

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.

Most of the time the fix is small. Seeing the failure clearly is the part that actually costs you.