# Is it necessary to have the "nstxout"?

**URL:** <https://gromacs.bioexcel.eu/t/is-it-necessary-to-have-the-nstxout/1555>\
**Category:** User discussions\
**Created:** [February 8, 2021, 4:05pm UTC](https://gromacs.bioexcel.eu/t/is-it-necessary-to-have-the-nstxout/1555 "2021-02-08T16:05:39Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![lanselibai](https://avatars.discourse-cdn.com/v4/letter/l/e9c0ed/32.png) [@lanselibai](https://gromacs.bioexcel.eu/u/lanselibai)\
**Post date:** [February 8, 2021, 4:05pm UTC](https://gromacs.bioexcel.eu/t/is-it-necessary-to-have-the-nstxout/1555/1 "2021-02-08T16:05:39Z")

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GROMACS version: 2020  
GROMACS modification: Yes/  
Here post your question

Hi, if I set `nstxout` as 0 while `nstxout-compressed` as 50000 (i.e. 100 ps interval), would it harm the simulation? I only need the coordinate file, so` xtc` file is sufficient for me, and I do not need the big `trr` file.

Is that correct that with or without the `trr` file has no impact on the simulation?

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**Author:** ![jalemkul](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/jalemkul/32/18_2.png) [@jalemkul](https://gromacs.bioexcel.eu/u/jalemkul)\
**Post date:** [February 8, 2021, 6:06pm UTC](https://gromacs.bioexcel.eu/t/is-it-necessary-to-have-the-nstxout/1555/2 "2021-02-08T18:06:16Z")

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> [@lanselibai](#):
>
> Is that correct that with or without the `trr` file has no impact on the simulation?

Correct.