# Comparing Simulations with Different Thermo/Barostats

**URL:** <https://gromacs.bioexcel.eu/t/comparing-simulations-with-different-thermo-barostats/13128>\
**Category:** User discussions\
**Tags:** mdp-parameters, mdrun\
**Created:** [January 20, 2026, 1:23pm UTC](https://gromacs.bioexcel.eu/t/comparing-simulations-with-different-thermo-barostats/13128 "2026-01-20T13:23:06Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![GabrielVA](https://avatars.discourse-cdn.com/v4/letter/g/f0a364/32.png) [@GabrielVA](https://gromacs.bioexcel.eu/u/GabrielVA)\
**Post date:** [January 20, 2026, 1:23pm UTC](https://gromacs.bioexcel.eu/t/comparing-simulations-with-different-thermo-barostats/13128/1 "2026-01-20T13:23:06Z")

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GROMACS version: 2023.5  
GROMACS modification: No  
Hi! I’ve been simulating different large protein-membrane systems (\> 500k atoms) for a while now to investigate the oligomerisation and membrane interaction of my protein of study. I’ve always prepared the systems with CharmmGUI, but I just noticed that my most recent simulations run with different thermo/barostats to the previous simulations. They switched from Nose-Hoover/Parrinello-Rahman to v-rescale/c-rescale. The rest of the parameters in the mdp file are the same. Here is my latest mdp version:

> ```auto
> integrator = md
> dt = 0.002
> nsteps = 500000
> nstxout-compressed = 50000
> nstxout = 0
> nstvout = 0
> nstfout = 0
> nstcalcenergy = 100
> nstenergy = 1000
> nstlog = 1000
> ;
> cutoff-scheme = Verlet
> nstlist = 20
> rlist = 1.2
> vdwtype = Cut-off
> vdw-modifier = Force-switch
> rvdw_switch = 1.0
> rvdw = 1.2
> coulombtype = PME
> rcoulomb = 1.2
> ;
> tcoupl = v-rescale
> tc_grps = SOLU MEMB SOLV
> tau_t = 1.0 1.0 1.0
> ref_t = 303.15 303.15 303.15
> ;
> pcoupl = C-rescale
> pcoupltype = semiisotropic
> tau_p = 5.0
> compressibility = 4.5e-5 4.5e-5
> ref_p = 1.0 1.0
> ;
> constraints = h-bonds
> constraint_algorithm = LINCS
> continuation = yes
> ;
> nstcomm = 100
> comm_mode = linear
> comm_grps = SOLU_MEMB SOLV
> 
> ```

While I’ve seen on the forum that v-rescale and c-rescale are highly recommended now, I worry that my simulations may not be comparable between them. For instance, if we publish a paper including results from two or more protein-membrane systems (such as the wild-type protein and a mutated version, or different order oligomers, or membrane placements) that have been simulated with different thermo/barostats.

Should I worry about this or is this not a fatal mistake?

Thank you in advance.

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<div class="post-metadata">

**Author:** ![hess](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/hess/32/416_2.png) [@hess](https://gromacs.bioexcel.eu/u/hess)\
**Post date:** [January 21, 2026, 10:16am UTC](https://gromacs.bioexcel.eu/t/comparing-simulations-with-different-thermo-barostats/13128/2 "2026-01-21T10:16:10Z")

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All thermostats and barostats, assuming the algorithms are correct and parameters reasonable, should produce the same ensemble. So the choice should not affect the results. With that said, second order algorithms, such as Nose-Hoover and Parrinello-Rahman, can cause instabilities, so that is why we recommend first order coupling.

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**Author:** ![GabrielVA](https://avatars.discourse-cdn.com/v4/letter/g/f0a364/32.png) [@GabrielVA](https://gromacs.bioexcel.eu/u/GabrielVA)\
**Post date:** [January 21, 2026, 10:23am UTC](https://gromacs.bioexcel.eu/t/comparing-simulations-with-different-thermo-barostats/13128/3 "2026-01-21T10:23:37Z")

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Well that’s very good news then. Thank you for your answer. Have a good day! :)