# Does Mac M1 in multithreads is slower that in single thread?

**URL:** https://discourse.julialang.org/t/does-mac-m1-in-multithreads-is-slower-that-in-single-thread/61114
**Category:** Performance
**Tags:** mac-m1
**Created:** [May 13, 2021, 11:48pm UTC](https://discourse.julialang.org/t/does-mac-m1-in-multithreads-is-slower-that-in-single-thread/61114 "2021-05-13T23:48:15Z")
**Posts on this page:** 1
**Showing post:** 12

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### Author: ![staticfloat](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/staticfloat/32/34_2.png) [@staticfloat](https://discourse.julialang.org/u/staticfloat)
#### Post date: [May 14, 2021, 3:34pm UTC](https://discourse.julialang.org/t/does-mac-m1-in-multithreads-is-slower-that-in-single-thread/61114/12 "2021-05-14T15:34:54Z")

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You can use `BLAS.lbt_forward("/System/Library/Frameworks/Accelerate.framework/Versions/A/Accelerate")` to start forwarding to Accelerate, but it’s LP64, so you can’t use Julia’s native `*` to do GEMM (since that will expect ILP64, and will thus still dispatch to OpenBLAS), you need to write your own wrapper. [The full gist](https://gist.github.com/staticfloat/ce81a163807633748e414e2f3c628062) has a demonstration.

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