Oracle Sun Netra X4270, Service Manual

Page: 134 / 238

Replacing DIMMs
Related Information
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“DIMM Considerations and Limitations” on page 135
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“DIMM Rank Classification Labels” on page 136
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“Error Correction and Parity” on page 136
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“Identify and Remove Faulty DIMMs” on page 137
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“Install DIMMs” on page 141
DIMM Population Rules
The DIMM population rules are as follows:
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Do not populate any DIMM sockets next to an empty CPU socket. Each processor contains
a separate memory controller.
■
Each CPU can support a maximum of:
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Nine dual-rank (DR) or single-rank (SR) DIMMs; or
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Six quad-rank (QR) DIMMs with two per memory channel; or
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Three QR DIMMs with one per channel and three DR or SR DIMMs.
■
Populate DIMMs by location according to the following rules (see “DIMM and CPU
Physical Layout” on page 133 for DIMM slot numbering):
■
Populate the DIMM slots for each memory channel that are the farthest from the CPU
first.
For example, populate D8/D5/D2 first; then D7/D4/D1 second; and finally, D6/D3/D0.
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Populate QR DIMMs first, followed by SR or DR DIMMs.
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Populate QR DIMMs in blue sockets (D8/D5/D2) first then white sockets (D7/D4/D1).
Note that QR DIMMs are supported only in white sockets if adjacent blue socket
contains a QR DIMM.
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Populate QR, SR, or DR DIMMs in sets of three for each CPU, one per memory
channel.
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For maximum performance, apply the following rules:
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Preserve DIMM symmetry to ensure the best performance. For example, add 3x of same
kind DIMMs, one per memory channel. Also, if the server has two CPUs, ensure that
both CPUs have the same size of DIMMs populated in the same manner.
■
In certain configurations, DIMMs will run slower than their individual maximum speed.
See “DIMM Considerations and Limitations” on page 135 for more information.
134 Sun Netra X4270 Server • September 2015