# Is rebuilding the system image necessary?

**URL:** <https://discourse.julialang.org/t/is-rebuilding-the-system-image-necessary/11078>\
**Category:** Performance\
**Created:** [May 22, 2018, 5:44pm UTC](https://discourse.julialang.org/t/is-rebuilding-the-system-image-necessary/11078 "2018-05-22T17:44:58Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![drinkwell](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/drinkwell/32/4212_2.png) [@drinkwell](https://discourse.julialang.org/u/drinkwell)\
**Post date:** [May 22, 2018, 5:44pm UTC](https://discourse.julialang.org/t/is-rebuilding-the-system-image-necessary/11078/1 "2018-05-22T17:44:58Z")

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I remember reading [this](http://www.stochasticlifestyle.com/7-julia-gotchas-handle/) blog post by @ChrisRackauckas a while ago. ‘Gotcha #7’ mentions rebuilding the system image so that you get hardware specific optimisations. Is this still necessary?

I’m using JuliaPro in case it’s relevant.

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**Author:** ![mauro3](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mauro3/32/292_2.png) [@mauro3](https://discourse.julialang.org/u/mauro3)\
**Post date:** [May 23, 2018, 7:54am UTC](https://discourse.julialang.org/t/is-rebuilding-the-system-image-necessary/11078/2 "2018-05-23T07:54:59Z")

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My understanding is that it is probably not necessary anymore for 0.7, but I find the docs a bit hard to read: [https://docs.julialang.org/en/latest/devdocs/sysimg/](https://docs.julialang.org/en/latest/devdocs/sysimg/)