# Flux running slow?

**URL:** <https://discourse.julialang.org/t/flux-running-slow/46032>\
**Category:** Machine Learning\
**Created:** [September 3, 2020, 11:19pm UTC](https://discourse.julialang.org/t/flux-running-slow/46032 "2020-09-03T23:19:39Z")\
**Posts on this page:** 1\
**Showing post:** 8

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**Author:** ![ToucheSir](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/touchesir/32/14411_2.png) [@ToucheSir](https://discourse.julialang.org/u/ToucheSir)\
**Post date:** [September 4, 2020, 4:31am UTC](https://discourse.julialang.org/t/flux-running-slow/46032/8 "2020-09-04T04:31:50Z")

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Ah, just noticed you’re running on Cpu with tanh activations. [Flux vs pytorch cpu performance](https://discourse.julialang.org/t/flux-vs-pytorch-cpu-performance/42667) is most likely the culprit (long story short, small dense MLPs with tanh on CPU hit a bunch of areas in Flux that need to be optimized), except more or less pronounced because you’re also running the backwards pass.

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