Oracle EXADATA X6-2, Service Manual, Page: 88 / 284

Servicing the DIMMs (CRU)
88 Oracle Server X6-2 Service Manual • June 2016
you must replace the failed DIMM with a DIMM of the same size (in gigabytes) and type
(quad-rank or dual-rank). In this scenario, you should not change the DIMM configuration.
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You have purchased new DIMMs and you want to use them to upgrade the server's memory.
In this scenario, you should adhere to DIMM population rules and follow the recommended
DIMM population order for optimal system performance.
Related Information
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“DIMM Population Rules” on page 88
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“Populating DIMMs for Optimal System Performance” on page 88
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“Using the Server Fault Remind Button” on page 92
DIMM Population Rules
The population rules for adding DIMMs to the server are as follows:
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The server supports 64-GB quad-rank (QR) Load-Reduced DIMMs (LRDIMMs) and 32-
GB dual-rank (DR) and 16-GB DR Registered DIMMs (RDIMMs).
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Do not mix 64-GB LRDIMMs and 16-GB or 32-GB RDIMMs in the same server. If the
server has 64-GB LRDIMMs installed, you cannot install 16-GB or 32-GB RDIMMs and
vice versa.
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Within a memory channel, DIMMs must be populated in the black sockets first, then in the
black sockets with white tabs, and then in the white sockets.
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If you are installing a mix of RDIMM sizes (for example, 16-GB and 32-GB), install the
larger size RDIMMs first, then the smaller RDIMMs, until all of the RDIMMs are installed.
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There are no restrictions on the minimum number of DIMM sockets that must be populated.
The server will operate properly with one DIMM installed.
Populating DIMMs for Optimal System
Performance
Optimal performance is achieved by populating the DIMMs so that the memory is symmetrical,
or balanced. Symmetry is achieved by adhering to the following guidelines:
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In single-processor systems, populate DIMMs of the same size in multiples of four.
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In dual-processor systems, populate DIMMs of the same size in multiples of eight.
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Populate the DIMM sockets in the order described in the following sections.
The following sections provide an example of how to populate the DIMM sockets to achieve
optimal system performance.