About the paralleling efficiency of MS 5.5-Dmol

I have a question about MS 5.5-dmol3.Nomater the Dmol3 installed in the alone computer and clusters, the paralleling efficiency is very low.When I sign in the computing nodes.And type 'top' ,the results is as follows:

Mem:  24547936k total, 23460912k used,  1087024k free,   256452k buffers
Swap: 24579440k total,        0k used, 24579440k free, 21848220k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND                                                                                               
9669 guanzy    18   0  274m  72m  15m R 233.7  0.3   1:41.21 dmol3_mpi.exe                                                                                         
9670 guanzy    16   0  272m  70m  15m R 221.7  0.3   1:39.04 dmol3_mpi.exe                                                                                         
9668 guanzy    18   0  277m  75m  16m R 200.8  0.3   1:40.26 dmol3_mpi.exe                                                                                         
9666 guanzy    18   0  277m  76m  18m R 181.6  0.3   1:55.15 dmol3_mpi.exe                                                                                         
9667 guanzy    18   0  275m  73m  16m R 167.9  0.3   1:48.63 dmol3_mpi.exe                                                                                         
9671 guanzy    18   0  273m  72m  15m R 167.9  0.3   1:43.63 dmol3_mpi.exe                                                                                         
9673 guanzy    18   0  273m  70m  15m R 156.0  0.3   1:43.91 dmol3_mpi.exe                                                                                         
9672 guanzy    18   0  273m  73m  15m R 154.0  0.3   1:50.73 dmol3_mpi.exe  

    The OS is CentOS and HP-MPI in the MS5.5

The bashrc is as follows:

# Parallel Environment Setting for Materials Studio 5.5

export MS_INSTALL_ROOT=/home/guanzy/Accelrys/MaterialsStudio55

export DMOL3_DATA=\$MS_INSTALL_ROOT/share/Resources/Quantum/DMol3

export DMOL_TMP=~/tmp

export LD_LIBRARY_PATH=\$LD_LIBRARY_PATH:/home/guanzy/Accelrys/LicensePack/linux/lib

export LD_LIBRARY_PATH=\$LD_LIBRARY_PATH:\$MS_INSTALL_ROOT/lib

export TMPDIR=\$DMOL_TMP

export PATH=\$PATH:\$MS_INSTALL_ROOT/etc/DMol3/bin

. ~/Accelrys/LicensePack/etc/lp_profile

eval `/home/guanzy/Accelrys/MaterialsStudio55/share/license/data/lic_setup.sh \$MS_INSTALL_ROOT/ -s sh` # Parallel Environment Setting for Materials Studio 5.5
export MS_INSTALL_ROOT=/home/guanzy/Accelrys/MaterialsStudio55
export DMOL3_DATA=\$MS_INSTALL_ROOT/share/Resources/Quantum/DMol3
export DMOL_TMP=~/tmp
export LD_LIBRARY_PATH=\$LD_LIBRARY_PATH:/home/guanzy/Accelrys/LicensePack/linux/lib
export LD_LIBRARY_PATH=\$LD_LIBRARY_PATH:\$MS_INSTALL_ROOT/lib
export TMPDIR=\$DMOL_TMP
export PATH=\$PATH:\$MS_INSTALL_ROOT/etc/DMol3/bin
. ~/Accelrys/LicensePack/etc/lp_profile
eval `/home/guanzy/Accelrys/MaterialsStudio55/share/license/data/lic_setup.sh \$MS_INSTALL_ROOT/ -s sh`

What's the matter? Any suggetions???