# Command Line Interface (CLI) much slower compared to starting in separate python environment

**URL:** <https://discourse.slicer.org/t/command-line-interface-cli-much-slower-compared-to-starting-in-separate-python-environment/19042>\
**Category:** Development\
**Tags:** python, cli\
**Created:** [August 3, 2021, 3:17pm UTC](https://discourse.slicer.org/t/command-line-interface-cli-much-slower-compared-to-starting-in-separate-python-environment/19042 "2021-08-03T15:17:11Z")\
**Posts on this page:** 1\
**Showing post:** 5

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [August 3, 2021, 6:01pm UTC](https://discourse.slicer.org/t/command-line-interface-cli-much-slower-compared-to-starting-in-separate-python-environment/19042/5 "2021-08-03T18:01:48Z")

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Do you see a difference in update rate if you don’t continuously print out a lot of text?

If that does not help then the best is to use a Python profiler instead of trying to guess what takes a long time (see how we did it [here](https://discourse.slicer.org/t/third-party-library-works-slower-inside-slicers-python-shell-why-how-to-do-performance-profiling/18742/2)).

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_[View the full topic](https://discourse.slicer.org/t/command-line-interface-cli-much-slower-compared-to-starting-in-separate-python-environment/19042)._