Contents
Unreal Engine 5.8 · Focused reference
Hitches, loading, and garbage collection
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Capture a hitch
- Set an explicit hitch threshold for the target experience; use
stat hitchesorstat dumphitchesfor fast detection where useful. - Display
stat unitgraph, togglestat raw, and reproduce the hitch. - Add bookmarks immediately before/after the action that triggers it.
- Trace
cpu,frame,bookmarkplus only the suspected channel:loadtime,file, orstats. - Inspect the exact slow frame and the preceding work; asynchronous requests often cause a later wait.
Symptom routing
| Hitch shape | Inspect |
|---|---|
| first use of asset/effect | async load, shader/PSO readiness, construction, audio decode |
| periodic spike | GC, streaming update, autosave/telemetry, scheduled subsystem |
| entering region | World Partition/level/texture/Nanite streaming and file IO |
| mass spawn/despawn | object construction, registration, physics/nav, GC pressure |
| camera cut | visibility burst, VSM pages, streaming, post/upscaler history |
For loading, correlate Asset Loading events with file reads and Game-thread waits. A long async load is not necessarily a hitch unless the critical thread blocks for it or the workload saturates IO/CPU.
For GC, inspect allocation/object churn before the collection, collection duration, unreachable-object processing, and post-GC work. Reduce avoidable churn or distribute work; do not merely raise the GC interval if that creates a larger eventual pause or excess memory.
Sources and version
Documentation target: Unreal Engine 5.8. Confirm behavior in your installed engine; no per-procedure test result is implied.
Read this system’s sources and verification notes →
Canonical reference and AI copy
unreal-insights-profiling/references/hitches-loading-and-gc.md