Multiple processes per node on a cluster

[MOLPRO]

With Nick's and Peter's help (thanks guys!), I have been able to get MOLPRO 
running in parallel on my cluster.  Now I have a question:

I managed to locate the procgrp file location (for the stout hearted, it's 
/usr/local/lib/molpro-mpp-Linux-i686-i4-2002.6) and specified my own (which 
works just fine).  The general form of the content of the procgrp file is:

user node number_of_processes path_to_executable work_directory

In my case, specifically, the contents are (simplified for this discussion)

root     n01 2 /usr/molprop_2002_6_p4_tcgmsg.exe /s1
root     n02 2 /usr/molprop_2002_6_p4_tcgmsg.exe /s1
root     n03 2 /usr/molprop_2002_6_p4_tcgmsg.exe /s1
root     n04 2 /usr/molprop_2002_6_p4_tcgmsg.exe /s1

Is this functionally the same as:

root     n01 2 /usr/molprop_2002_6_p4_tcgmsg.exe /s1
root     n01 2 /usr/molprop_2002_6_p4_tcgmsg.exe /s2
root     n02 2 /usr/molprop_2002_6_p4_tcgmsg.exe /s1
root     n02 2 /usr/molprop_2002_6_p4_tcgmsg.exe /s2
root     n03 2 /usr/molprop_2002_6_p4_tcgmsg.exe /s1
root     n03 2 /usr/molprop_2002_6_p4_tcgmsg.exe /s2
root     n04 2 /usr/molprop_2002_6_p4_tcgmsg.exe /s1
root     n04 2 /usr/molprop_2002_6_p4_tcgmsg.exe /s2

?

When I run each choice of procgrp, I see no net effect on 'real' time.  Under 
MPICH, with other software, I can specify the second type of procgrp and see 
a substantial reduction in real time since each processor is treated as a 
separate instance of that executable.

Am I correct in my conclusion that MOLPRO/ Global Arrays does not do the same 
as MPICH?  Does MOLPRO/ Global Arrays take the specification of 2 processes 
for a node and just turn on SMP processing?  Is there a way I can get MOLPRO 
to provide the same behavior I have seen with MPICH?

Any insight that anyone can provide would be appreciated.

Also, does anyone know why MOLPRO ignores the work_directoy specified in the 
procgrp file?

I will summarize responses to the list.

Jim