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Fixed in 5.3.3



Found in


Issue ID




[Perf] GISceneManager.Update taking ~90% processor time on scene start

Global Illumination


Reproduction steps:
1. Open the project ""
2. Open the profiler, and turn on "editor profiling"
3. Open the scene "_8Artois_HIGHMEM_ASSETBUNDLE"
Notice that GISceneManager.Update() is taking ~90% of processor time.
Notice that GI isn't even turned on.
If the project is closed after the lag stops, and started again, the lag will resume.

After several minutes, the performance will return to normal. The performance hit seems to depend on the number of objects in the scene.

I've attached a screenshot of the profiler screen. [Actually, FogBugz doesn't let me attach anything ATM (503 error), so if whoever reads this needs those files, I can send them over via slack.]

Comments (4)

  1. lrb

    Apr 22, 2019 18:22

    Still present at Unity 2017.4.22f1.

  2. noobz_from_poland

    Feb 26, 2018 08:34

    EDY's solution works in 2017.1

  3. Edy

    Jun 14, 2017 17:02

    Still present in 5.6.1p1 in large scenes with many objects.
    Workaround: Lighting > disable Auto-Generate, then Generate Lighting manually.

  4. rotor-games

    Nov 23, 2015 12:14

    this issue persists in 5.3.0f1, it's causing really unworkable editor performance.

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