Effect On Performance Of Using Mirroring Or Sparing - IBM System x3850 X5 Implementation Manual

These options are configured by using the UEFI during the boot sequence.

4.8.8 Effect on performance of using mirroring or sparing

To understand the effect on performance of selecting various memory modes, we use a
system configured with X7560 processors and populated with sixty-four 4 GB quad-rank
DIMMs.
Figure 4-19 shows the peak system-level memory throughput for various memory modes
measured using an IBM-internal memory load generation tool. As shown, there is a 50%
decrease in peak memory throughput when going from a normal (non-mirrored) configuration
to a mirrored memory configuration.
Figure 4-19 Relative memory throughput by memory mode
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IBM eX5 Implementation Guide
Relative Memory Throughput by Memory Mode
Sparing
Mirroring
Normal
0 20
62
50
40 60 80
Relative Memory Throughput
100
100 120