Intel SR1690WB - Server System - 0 MB RAM, Service Manual

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22 Intel
®
Server System SR1690WB Service Guide
Figure 12. Channel Slots Configuration
The Independent Channel Mode is the default Maximum Performance Mode preferred for
Intel
®
Xeon
®
Processor 5500 series and Intel
®
Xeon
®
Processor 5600 series based
platforms. All three channels may be populated in any order and have no matching
requirements. All channels must run at the same interface frequency, but individual
channels may run at different DIMM timings (RAS latency, CAS latency, and so forth).
Memory Sparing and Mirroring
The spare mode is not supported by Intel
®
Server System SR1690WB.
With memory mirroring, the system maintains two copies of all data in the memory
subsystem. If a DIMM fails, the data is not lost because the second copy of the data is
available from the mirrored DIMM in the opposite channel. The system will not fail due
to memory error unless both the primary and the mirrored copy of the data become corrupt
at the same time.
In a mirrored system, the maximum usable memory is one-half of the installed memory,
with a minimum of two DIMMs installed. Since the data is duplicated across DIMMs, it
means that up to one-half of the installed DIMMs are actively in use at any one time. The
remaining DIMMs are used for mirroring.