Dell PowerEdge R740xd - General Memory Module Installation Guidelines; NVDIMM-N Memory Module Installation Guidelines; Mode-Specific Guidelines

General memory module installation guidelines
NOTE: If your system's memory congurations fail to observe these guidelines, your system might not boot, might stop
responding during memory conguration, or might operate with reduced memory.
The system supports Flexible Memory Conguration, enabling the system to be congured and run in any valid chipset architectural
conguration. The following are the recommended guidelines for installing memory modules:
• RDIMMs and LRDIMMs must not be mixed.
• x4 and x8 DRAM based memory modules can be mixed. For more information, see the Mode-specic guidelines section.
• Up to two RDIMMs can be populated per channel regardless of rank count.
• Up to two LRDIMMs can be populated per channel regardless of rank count.
• If memory modules with dierent speeds are installed, they will operate at the speed of the slowest installed memory module(s) or
slower depending on the system DIMM conguration.
• 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 rst, followed by the black release tabs.
• When mixing memory modules with dierent capacities, populate the sockets with memory modules with the highest capacity rst. For
example, if you want to mix 8 GB and 16 GB memory modules, populate 16 GB memory modules in the sockets with white release tabs
and 8 GB memory modules in the sockets with black release tabs.
• In a dual-processor conguration, the memory conguration 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 dierent capacities can be mixed provided other memory population rules are followed (for example, 8 GB and 16
GB memory modules can be mixed).
• Mixing of more than two memory module capacities in a system is not supported.
• Populate six memory modules per processor (one DIMM per channel) at a time to maximize performance.
Related link
Mode-specic guidelines
NVDIMM-N memory module installation guidelines
The following are the recommended guidelines for installing NVDIMM-N memory modules:
• Each system supports memory congurations with 1, 2, 4, 6, or 12 NVDIMM-Ns.
• Supported congurations have dual processors and a minimum of 12x RDIMMs.
• LRDIMMS and NVDIMM-Ns must not be mixed.
• Maximum of 12 NVDIMM-Ns can be installed in a system.
For more information on the supported NVDIMM-N congurations, see the NVDIMM-N User Guide at Dell.com/poweredgemanuals.
Mode-specic guidelines
Six memory channels are allocated to each processor. The congurations allowed depend on the memory mode selected.
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Installing and removing system components