Memory performance on HP Z840/Z640/Z440 Workstation

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Technical white paper | Memory performance on HP Z840/Z640/Z440 Workstations
Figure 9. HP Z840 Energy and Life Sciences
FFTW
SPECwpc - Energy SPECwpc – Life Sciences
SRMP LAMMPS NAMD Rodinia
Relative performance
1.10
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
1.00
0.84
0.61
1.00
0.82
0.58
1.00
0.88
1.00
0.91
0.74
0.73
0.40
1.00
Results discussion
The comparison results shown above hold to the general rule: single or lightly threaded applications and workloads
that do not require or use signicant memory bandwidth will experience a smaller performance impact moving to
larger memory DIMMs, in conjunction with populating fewer memory channels. This can be seen in some of the Product
Development results, namely Autodesk® AutoCAD, Solidworks and NX. These applications are lightly threaded and
the particular workloads used for these runs use very little of the available memory bandwidth, so any performance
dierence seen due to the memory channel loading would be predicted to be small.
Of the Media and Entertainment applications and workloads evaluated, HandBrake is one that showed sustained use
of all the available cores and consistent, although not high, use of memory bandwidth. You can see that HandBrake
performance begins to be noticeably impacted by memory channel loading when there is only a single memory channel
loaded per processor.
In contrast, the WPCcfd results seen under the Product Development results show a signicant performance impact
moving to larger memory DIMMs while populating fewer memory channels. This application and workload has sustained
use of all the available cores and uses signicant memory bandwidth. This can also be seen in the FFTW, SRMP, LAMMPS
and Rodinia results shown under the Energy and Life Sciences benchmarks.
8 x 4 GB DIMMs
(32 GB - 4 ch loaded/CPU)
4 x 8 GB DIMMs
(32 GB - 2 ch loaded/CPU)
4 x 4 GB DIMMs
(16 GB - 2 ch loaded/CPU)
2 x 8 GB DIMMs
(16 GB - 1 ch loaded/CPU)
Comparison 2Comparison 1