The version of Qs used is dated September, 10th, 2004. The parallel version was compiled with

mpicc -DMPI -static -I/usr/local/include -O3 -unroll -tpp6 -xK -wp_ipo Qs_working.c -lsrfftw_intel -lsfftw_intel -limf -lm

where mpicc resolves to

icc -O2 -tpp6 -DUSE_STDARG -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_UNISTD_H=1 -DHAVE_STDARG_H=1 -DUSE_STDARG=1 -DMALLOC_RET_VOID=1 -L/usr/local/mpich-ssh/lib -lmpich

Before measuring (using wall-clock time) the performance of the program, a comparison was made between running Qs with a simple 'mpirun' command, and running it via SGE. The setting for this test was

4156 unique reflections
Space group P422
100000 steps per minimisation
1 minimisation
4 processors (server + 3 celerons) The results were

Method	Wall-clock time
mpirun	919 seconds
Grid Engine	894 seconds

The tests : Celerons & server

The parameters tested are

Number of unique reflections
Number of crystallographic symmetry operators (space group)
Number of processors

In all cases only one minimisation was performed lasting 100,000 steps. The results are :

8 symmetry operators

Reflections	Space group	Processors	Wall-clock time in seconds	Scale-up
4156	P422	1 (celeron)	2032	1.000
4156	P422	1 (Pentium IV)	1690	1.202
4156	P422	2 (mixed)	1241	1.637
4156	P422	4	894	2.272
4156	P422	6	802	2.533
4156	P422	8	753	2.698

Reflections Space group Processors Wall-clock time in seconds Scale-up
2049 P422 1 (celeron) 1058 1.000
2049 P422 1 (Pentium IV) 818 1.293
2049 P422 2 664 1.593
2049 P422 4 500 2.116
2049 P422 6 487 2.172
2049 P422 8 449 2.356

Reflections Space group Processors Wall-clock time in seconds Scale-up
8224 P422 1 (celeron) 4148 1.000
8224 P422 1 (Pentium IV) 3449 1.202
8224 P422 2 2377 1.745
8224 P422 4 1685 2.501
8224 P422 6 1564 2.652
8224 P422 8 1329 3.121

4 symmetry operators

Reflections	Space group	Processors	Wall-clock time in seconds	Scale-up
4156	P222	1 (celeron)	1056	1.000
4156	P222	1 (Pentium IV)	870	1.213
4156	P222	2 (mixed)	752	1.404
4156	P222	4	659	1.602
4156	P222	6	661	1.597
4156	P222	8	650	1.624

Reflections Space group Processors Wall-clock time in seconds Scale-up
2049 P222 1 (celeron) 568 1.000
2049 P222 1 (Pentium IV) 428 1.327
2049 P222 2 409 1.388
2049 P222 4 374 1.518
2049 P222 6 401 1.416
2049 P222 8 408 1.392

Reflections Space group Processors Wall-clock time in seconds Scale-up
8224 P222 1 (celeron) 2180 1.000
8224 P222 1 (Pentium IV) 1796 1.213
8224 P222 2 1466 1.487
8224 P222 4 1211 1.800
8224 P222 6 1158 1.882
8224 P222 8 1114 1.956

2 symmetry operators

Reflections	Space group	Processors	Wall-clock time in seconds	Scale-up
10044	P2	1 (celeron)	1464	1.000
10044	P2	1 (Pentium IV)	1208	1.211
10044	P2	2 (mixed)	1215	1.204
10044	P2	4	1163	1.258
10044	P2	6	1216	1.203

Reflections Space group Processors Wall-clock time in seconds Scale-up
19879 P2 1 (celeron) 2718 1.000
19879 P2 1 (Pentium IV) 2271 1.196
19879 P2 2 (mixed) 2321 1.171
19879 P2 4 2169 1.253
19879 P2 6 2158 1.259

Conclusions

On the newer nodes :