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6.9 Configuring for the Fast Memory Mode
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One of the following partition configurations must be used:
[ (SB#00, SB#01) ]
[ ]: Partition configuration
( ): Interleaved set
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Memory modules must be fully mounted on each system board within an
applicable partition.
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All the memory modules that are mounted on each system board within an
applicable partition must have the same capacity.
(3)
Setup procedure
a) Normal interleave mode
No special settings are required.
b) Extended interleave mode
The settings are to be made with “Machine Administration Menu” of System Console
Software. For details, refer to the “System Console Software User's Guide”.
(4)
Notes
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For partitions for which extended interleave modes are set, DR function cannot be
used.
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To enable the extended interleave mode, it is necessary to turn off the power of the
main unit and then turn it on again.
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If degraded operation for memory modules or system boards occurs, the interleave
modes being used are automatically canceled, the normal mode is restored, and
then the system is activated.
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It takes a little longer for the system to be activated.
6.9.2
4CPU mode
• Overview
Up to eight CPUs can be installed on the system board of the PRIMEPOWER900.
Addresses and data are divided into two parts (each part uses four CPUs) and are
controlled separately. Therefore, if the system contains four or fewer CPUs and the
memory module installation pattern has a 1-way configuration, only one part of the
system is operated. This single-part operation mode is called the “4CPU mode”. In
4CPU mode, eliminating unnecessary data transfer can reduce the memory latency,
yielding increased performance.
