Dear:<br><br>  I am using gromacs for membrane simulation (under CHARMM36 FF) which contains around 80,000 atoms. I&#39;ve submitted over 200 CPU in the cluster for such system with 2 fs time step. And what really astonished is that the efficiency for such simulation is only 3ns/day..... I am wondering what happen to my system or gromacs? What can I do to fasten the simulation?<br>
<br>here is my md.mdp:<br><i><br>title                    = god!<br>cpp                      = /usr/bin/cpp<br>include                  = <br>define                   = <br>integrator               = md<br>dt                       = 0.001<br>
nsteps                   = 100000000<br>nstxout                  = 1000000<br>nstvout                  = 1000000<br>nstlog                   = 1000000<br>nstenergy                = 10000<br>nstxtcout                = 100000<br>
xtc_grps                 =<br>energygrps         = Protein POPC SOL ION<br>nstcalcenergy            = 1<br>nstlist                  = 1<br>nstcomm                  = 1<br>comm_mode                = Linear<br>comm-grps                = Protein_POPC    Water_and_ions<br>
ns_type                  = grid<br>rlist                    = 1.2<br>rlistlong         = 1.4<br>vdwtype             = Switch<br>rvdw                     = 1.2<br>rvdw_switch         = 0.8<br>coulombtype              = pme<br>
rcoulomb                 = 1.2<br>rcoulomb_switch         = 0.0<br>fourierspacing         = 0.15<br>pme_order         = 4<br>DispCorr             = no<br>tcoupl                   = nose-hoover<br>nhchainlength            = 1<br>
tc-grps                  = Protein_POPC    Water_and_ions<br>tau_t                    = 0.5            0.5<br>ref_t                    = 310         310<br>Pcoupl                   = parrinello-rahman<br>Pcoupltype               = semiisotropic<br>
tau_p                    = 5.0<br>compressibility          = 4.5e-5       4.5e-5<br>ref_p                    = 1.0          1.0<br>pbc             = xyz<br>gen_vel                  = no<br>optimize_fft         = no<br>constraints              = hbonds<br>
constraint_algorithm     = Lincs     <br></i><br><br><br>Thank you very much<br><br>best<br>