General Memory Module Installation Guidelines; Mode-Specific Guidelines - Dell EMC VxRail P470 Owner's Manual

DIMM Type DIMMs Populated/
Channel
LRDIMM 1
2
3

General memory module installation guidelines

NOTE: Memory configurations that fail to observe these guidelines can prevent your appliance from booting, stop responding
during memory configuration, or operating with reduced memory.
The appliance supports Flexible Memory Configuration, enabling the appliance to be configured and run in any valid chipset architectural
configuration. The following are the recommended guidelines for installing memory modules:
• RDIMMs and LRDIMMs must not be mixed.
• x16 and x32 DRAM based memory modules can be mixed. For more information, see the Mode-specific guidelines section.
• Up to three dual- or single-rank RDIMMs can be populated per channel.
• Up to three LRDIMMs can be populated per channel regardless of rank count.
• If memory modules with different speeds are installed, they will operate at the speed of the slowest installed memory module(s) or
slower depending on appliance DIMM configuration.
• Populate memory module sockets only if a processor is installed. For single-processor systems, sockets A1 to A12 are available. For
dual-processor systems, sockets A1 to A12 and sockets B1 to B12 are available.
• Populate all the sockets with white release tabs first, followed by the black release tabs, and then the green release tabs.
• Mixing of more than two memory module capacities in a appliance is not supported.
• When mixing memory modules with different capacities, populate the sockets with memory modules with highest capacity first. For
example, if you want to mix 16 GB and 32 GB memory modules, populate 32 GB memory modules in the sockets with white release
tabs and 16 GB memory modules in the sockets with black release tabs.
• In a dual-processor configuration, the memory configuration for each processor should be identical. For example, if you populate socket
A1 for processor 1, then populate socket B1 for processor 2, and so on.
• Memory modules of different 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 memory module capacities in a appliance is not supported.
• VxRail Appliances require that you populate four memory modules per processor (one DIMM per channel) at a time to maximize
performance.

Mode-specific guidelines

CAUTION: Dell EMC has optimized your appliance and recommends that you do not change any of these settings.
Four memory channels are allocated to each processor. The allowable configurations depend on the memory mode selected.
Advanced Error Correction Code (lockstep)
Advanced Error Correction Code (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.
The installation guidelines for memory modules are as follows:
• Memory modules must be identical in size, speed, and technology.
Operating Frequency (in
Voltage
2400, 2133, 1866
1.2 V 2400, 2133, 1866
2133, 1866
Maximum DIMM Rank/Channel
MT/s)
Quad rank
Quad rank
Quad rank
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