[gmx-users] mpirun problem

[ha salem]

dear users
     I have encouneterd a problem with mpirun I have 2 pc (every pc has 1 intel 
     quad core cpu) ,when I run mdrun on 1 machine with  "-np 4 " option the calculation
     run on 4 cores and goes faster ,system monitor show all 4 cores of this cpu are working
     every core has 90% cpu usage,and every thing is ok
     but now I connect 2 computer to LAN and I executed lamboot -v lamhosts
     then I run mpirun -np 8 but I see the all 8 cores of 2 machines are workinng with
     20 % 10% cpu usage and speed is lower than 4 cores of 1 cpu!!!!
     can you help me ?my molecule is part of hsa and is macro molecule
   these are my commands
usr/local/share/gromacs_331/bin/grompp -np 8 -f prmd.mdp -c finalprsp.gro -r finalprsp.gro -p n.top 
mpirun -np 8 /usr/local/share/gromacs_331/bin/mdrun -np 8 -s prmd.tpr -o prmd.trr -c finalprmd.gro -g prmd.log -e prmd.edr -n n.ndx




      
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