# Nstlist changing when running mdrun

**URL:** <https://gromacs.bioexcel.eu/t/nstlist-changing-when-running-mdrun/10238>\
**Category:** User discussions\
**Tags:** mdrun\
**Created:** [September 26, 2024, 10:28am UTC](https://gromacs.bioexcel.eu/t/nstlist-changing-when-running-mdrun/10238 "2024-09-26T10:28:02Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![CH68](https://avatars.discourse-cdn.com/v4/letter/c/6f9a4e/32.png) [@CH68](https://gromacs.bioexcel.eu/u/CH68)\
**Post date:** [September 26, 2024, 10:28am UTC](https://gromacs.bioexcel.eu/t/nstlist-changing-when-running-mdrun/10238/1 "2024-09-26T10:28:02Z")

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GROMACS version: 2024.3  
GROMACS modification: No  
Hi everyone,

I am running a simulation of a membrane protein embedded in a POPC membrane using CHARMM36m. I was wondering if anyone has some insight into why the nstlist value changes on its own. So far the simulations seems to behave normally. I get the following message:

Changing nstlist from 5 to 80, rlist from 1.2 to 1.364

Thank you!

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**Author:** ![MagnusL](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/magnusl/32/2380_2.png) [@MagnusL](https://gromacs.bioexcel.eu/u/MagnusL)\
**Post date:** [September 26, 2024, 11:02am UTC](https://gromacs.bioexcel.eu/t/nstlist-changing-when-running-mdrun/10238/2 "2024-09-26T11:02:40Z")

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The values are automatically changed to improve the performance. See [Molecular dynamics parameters (.mdp options) - GROMACS 2024.3 documentation](https://manual.gromacs.org/documentation/current/user-guide/mdp-options.html#mdp-nstlist) and [Molecular dynamics parameters (.mdp options) - GROMACS 2024.3 documentation](https://manual.gromacs.org/documentation/current/user-guide/mdp-options.html#mdp-verlet-buffer-tolerance) for some more information. As stated there, you can override the automatic tuning if there is any reason to do so.

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<div class="post-metadata">

**Author:** ![CH68](https://avatars.discourse-cdn.com/v4/letter/c/6f9a4e/32.png) [@CH68](https://gromacs.bioexcel.eu/u/CH68)\
**Post date:** [September 26, 2024, 12:00pm UTC](https://gromacs.bioexcel.eu/t/nstlist-changing-when-running-mdrun/10238/3 "2024-09-26T12:00:39Z")

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Thank you MagnusL!