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Fixed in 2017.1.X



Found in


Issue ID




10 times longer asset bundle building when building multiple small asset bundles

Asset Bundles


Steps to reproduce:
1. Download and open project ""
2. Click "Assets/Build AssetBundles" - 16 asset bundles each containing 1 picture will be built
3. Wait for building to finish
4. Take a look at console output

Result: it took Unity Editor about 40 seconds to build 16 assetbundles, about 10 times longer than before

Reproduced with: 5.5.0a4, 5.5.0b11 - took about 40 seconds to build

Not reproducible with: 5.4.2p4, 5.5.0a3 - took about 4 seconds to build

Regression introduced in 5.5.0a4

Comments (4)

  1. hyunlee

    Jun 19, 2017 12:44

    I'm not sure it is related to
    However, it is still reproduced on 5.6.1p3. Please fix this asap. Now, it takes 10 times longer when building asset bundles.

  2. ArtyBrest

    Apr 26, 2017 07:39

    It's fixed but could be better!
    We have more than 1500 asset bundles with different sizes (mostly small) and we have found that build process is constantly slowed down after each bundle build in queue. It takes more than 40 minutes to build them all in v5.6.0p1 (9 minutes in v5.6.0p2). But we have split build process to separate chunks so no more than 500 bundles will be build in one BuildPipeline.BuildAssetBundles call. Last call is contained all bundles to have proper AssetBundleManifest file. And now build time is 3 minutes (8 minutes before v5.6.0p2)!!!


  3. Games-Foundry

    Mar 29, 2017 22:01

    Issue remains in 5.5.2p4

  4. temps

    Mar 02, 2017 20:58

    We are seeing this too, we have a fairly large project and building assets in our current version 5.4.0p3, takes about 15 minutes. Now we are testing out 5.5.2p1 and building assets takes a lot longer time, at times it almost looks like the asset building has frozen.

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