Dell PowerEdge R820 - Manual (Page 16)

Performance Analysis of HPC Applications on Several Dell PowerEdge 12 th Generation Servers
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WRF performance Figure 7.
4.5. ANSYS Fluent
Two benchmark datasets, truck_poly_14m and truck_111m, are used for performance evaluation with
ANSYS Fluent. ANSYS Fluent is not sensitive to memory bandwidth but is sensitive to core speed. From
Figure 8, the Dell PowerEdge M420 performs 9 to 12 percent less than the PowerEdge M620. This can be
attributed to the 15 percent drop in CPU frequency when compared to the PowerEdge M620.
For the same dataset, the PowerEdge R820 performs 7 to 11 percent less than the PowerEdge M620
when the server is fully-subscribed. The difference in the number of QPI links, the number of turbo
bins and the turbo headroom available are possible factors that contribute to the drop in performance
on the PowerEdge R820. The 30 percent drop in memory bandwidth per core on the PowerEdge R820
when compared to the PowerEdge M620 is not considered a significant factor since ANSYS Fluent is not
memory bandwidth sensitive.
Figure 9 compares the performance among the three clusters when using the truck_111m benchmark
dataset. The minimum amount of memory required for the benchmark is 128GB. The PowerEdge M620
and PowerEdge M420 were configured with 64GB each. Allowing some space for the operating system, a
minimum of three servers is needed to run this benchmark data set. Similarly, a minimum of two
PowerEdge R820 servers (configured with 128GB memory each) is required to run truck_111m. Thus the
first data point plotted is with 64 cores and not 8, 16, or 32 cores. The PowerEdge R820 performs ~8
percent lower than the PowerEdge M620 and the PowerEdge M420 perform 8 to 11 percent lower than
the PowerEdge M620s. The trends and analysis are similar to the ones observed with the
truck_poly_14m data set.
0.71
0.85
0.89
1.29
1.12 1.11
0.87 0.86 0.86 0.84
0.90
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
256 128 64 32 16 8
Per
fo
rmance
R
el
at
ive
to
Power
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ge
M620
(H
ig
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is
B
et
ter
)
Number of Cores
M620-2.7GHz R820-2.7GHz M420-2.3GHz