# Wasm64 and Multithreading

**URL:** <https://discussions.unity.com/t/wasm64-and-multithreading/1735527>\
**Category:** Web\
**Tags:** Unity-for-Web, Question, 6.6\
**Created:** [September 2, 2026, 6:56pm UTC](https://discussions.unity.com/t/wasm64-and-multithreading/1735527 "2026-09-02T18:56:43Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![ferretnt](https://avatars.discourse-cdn.com/v4/letter/f/ccd318/32.png) [@ferretnt](https://discussions.unity.com/u/ferretnt)\
**Post date:** [September 2, 2026, 6:56pm UTC](https://discussions.unity.com/t/wasm64-and-multithreading/1735527/1 "2026-09-02T18:56:43Z")

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Yay, wasm64 support! And there was much rejoycing.

Until there wasn’t, because when you try, the choice is either Wasm64 OR Multithreading, and we need multithreading even more than we need \>4Gb.

Is there any plan to support, err, both at once? I imagine in the majority of cases where people want \>4Gb they’re also doing something that wants threads…

Is this related to [Memory64, multithreading and the 128-bit atomics operations to combat the ABA problem · Issue #253 · WebAssembly/threads · GitHub](https://github.com/webassembly/threads/issues/253)?

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**Author:** ![brendanduncan\_u3d](https://dub1.discourse-cdn.com/unity/user_avatar/discussions.unity.com/brendanduncan_u3d/32/882282_2.png) [@brendanduncan\_u3d](https://discussions.unity.com/u/brendanduncan_u3d)\
**Post date:** [September 2, 2026, 8:17pm UTC](https://discussions.unity.com/t/wasm64-and-multithreading/1735527/2 "2026-09-02T20:17:48Z")

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Wasm64 threading is being worked on, and yes, it is related to atomics. Alternative solutions are being investigated. It is an important feature to get working, but there aren’t any timeframe estimates currently.

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**Author:** ![ferretnt](https://avatars.discourse-cdn.com/v4/letter/f/ccd318/32.png) [@ferretnt](https://discussions.unity.com/u/ferretnt)\
**Post date:** [September 2, 2026, 8:27pm UTC](https://discussions.unity.com/t/wasm64-and-multithreading/1735527/3 "2026-09-02T20:27:20Z")

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Thanks Brendan! I did hack together a singlethreaded wasm64 build. It’s very, err, hitchy but having “more than an iPhone XS” amounts of RAM is amazing 🙂

As always, thanks to everybody at Unity pushing the whole web tech stack (threads, memory, webgpu, and being the drivers pushing the wider web performance ecosystem) forward.

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<div class="post-metadata">

**Author:** ![brendanduncan\_u3d](https://dub1.discourse-cdn.com/unity/user_avatar/discussions.unity.com/brendanduncan_u3d/32/882282_2.png) [@brendanduncan\_u3d](https://discussions.unity.com/u/brendanduncan_u3d)\
**Post date:** [September 2, 2026, 8:29pm UTC](https://discussions.unity.com/t/wasm64-and-multithreading/1735527/4 "2026-09-02T20:29:34Z")

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Now if we can get iOS to let you use more than 1GB of memory, that would be nice! 🙂