# ITK5 crashes on older CPUs

**URL:** https://discourse.itk.org/t/itk5-crashes-on-older-cpus/2250
**Category:** Engineering
**Created:** [September 19, 2019, 11:23pm UTC](https://discourse.itk.org/t/itk5-crashes-on-older-cpus/2250 "2019-09-19T23:23:30Z")
**Posts on this page:** 1
**Showing post:** 7

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### Author: ![mihail.isakov](https://discourse.itk.org/letter_avatar_proxy/v4/letter/m/c4cdca/32.png) [@mihail.isakov](https://discourse.itk.org/u/mihail.isakov)
#### Post date: [September 20, 2019, 7:41am UTC](https://discourse.itk.org/t/itk5-crashes-on-older-cpus/2250/7 "2019-09-20T07:41:12Z")

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I am glad i still build my public releases for Windows with ITK-4.13 and VS 2013. Not yet sure which flag is responsible for BMI2 instructions, but AVX2 is enough to make big problems, ITK5 build system on Windows forces to use [AVX2 and runs test program on build host](https://github.com/InsightSoftwareConsortium/ITK/blob/20eafe87a6ff778107f6df370001d450f95c1f4c/CMake/ITKSetStandardCompilerFlags.cmake#L175), but the test is useless for public releases. AVX2 was available on AMD hardware from Q2 2015. I definitely don’t want this in public release, too early, sorry. I don’t have very many users, but even if the number is small i don’t want upset some of them, who bought their hardware 3 years ago. Sorry.

![users](https://discourse.itk.org/uploads/default/original/1X/aa3875b518c19ef5dc45a7ff6172b7b77a7daab5.jpeg)

**Edit** : were interesting to see where in ITK the appropriate intrinsic functions are used. Just enabling SSE2/3/AVX or whatever SIMD may do nothing, performance gain may be zero, i would not wonder. I shall check…

**Edit** :  
Current hardware data from Steam (August 2019)

```
SSE2 100.00%
SSE3 100.00%
SSSE3 97.70%
SSE4.1 96.54%
SSE4.2 95.49%
AVX 89.29%
```

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