Owners Manual

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• x4 and x8 DRAM based DIMMs can be mixed. For more information, see Mode-specific guidelines.
• Up to two dual- or single-rank RDIMMs can be populated per channel.
• Populate DIMM sockets only if a processor is installed. For single-processor systems, sockets A1 – A8
are available. For dual-processor systems, sockets A1 – A8 and sockets B1 – B4 are available.
• Populate all sockets with white release levers first, and then all the sockets with black release levers.
• When mixing memory modules with dierent capacities, populate the sockets with memory modules
with highest capacity first. For example, if you want to mix 16 GB and 32 GB DIMMs, populate 32 GB
DIMMs in the sockets with white release levers and 16 GB DIMMs in the sockets with black release
levers.
• In a dual-processor configuration, the memory configuration for each processor should be identical
through the first eight slots. For example, if you populate socket A1 for processor 1, then populate
socket B1 for processor 2, and so on.
• Memory modules of dierent capacities can be mixed provided other memory population rules are
followed (for example, 16 GB and 32 GB memory modules can be mixed).
• Mixing of more than two DIMM capacities in a system is not supported.
• Populate two DIMMs per processor (one DIMM per channel) at a time to maximize performance.
Mode-specific guidelines
Four memory channels are allocated to each processor. The allowable configurations depend on the
memory mode selected.
NOTE: You can mix x4 and x8 DRAM based DIMMs to support RAS features. However, all guidelines
for specific RAS features must be followed. x4 DRAM based DIMMs retain Single Device Data
Correction (SDDC) in memory optimized (independent channel) mode. x8 DRAM based DIMMs
require Advanced ECC mode to gain SDDC.
The following sections provide additional slot population guidelines for each mode:
Advanced ECC (lockstep)
Advanced ECC mode extends SDDC from x4 DRAM based DIMMs to both x4 and x8 DRAMs. This
protects against single DRAM chip failures during normal operation.
Memory installation guidelines:
• Memory modules must be identical in size, speed, and technology.
• DIMMs installed in memory sockets with white release levers must be identical and similar rule applies
for sockets with black release levers. This ensures that identical DIMMs are installed in matched pairs
- for example, A1 with A2, A3 with A4, A5 with A6.
NOTE: Advanced ECC with Mirroring is not supported.
Memory optimized (independent channel) mode
This mode supports SDDC only for memory modules that use x4 device width, and the mode does not
impose any specific slot population requirements.
Memory sparing
NOTE: To use memory sparing, this feature must be enabled in the System Setup.