System Memory - Dell PowerEdge R930 Owner's Manual

System memory

Your system supports DDR4 ECC registered DIMMs (RDIMMs) and load reduced DIMMs (LRDIMMs) at
DDR4 (1.2V) voltage specification. It also supports single, dual and quad rank DIMMs of up to 1866 MHz.
NOTE: MT/s indicates DIMM speed in MegaTransfers per second.
Memory bus operating frequency can be 1333 MT/s, 1600 MT/s, and 1866 MT/s depending on:
• DIMM type (RDIMM and LRDIMM)
• DIMM configuration (number of ranks)
• Maximum frequency of the DIMMs
• Number of DIMMs populated per channel
• System profile selected (for example, Performance Optimized, Custom, or Dense Configuration
Optimized)
• Maximum supported DIMM frequency of the processors
The system memory contain 96 memory sockets organized into eight memory risers, split into four sets
of two risers per processor. Each memory riser has:
• 12 DIMM sockets arranged into four channels. In each channel, the release levers of the first socket
are marked white, the second socket black, and the third socket green.
• Two Scalable Memory Interconnect-2 (SMI-2) ports that help DIMMs to connect with the processor.
• Two Scalable Memory Buffers (SMB) that provide access to the DIMMs.
SMI-2 ports operate in two modes:
NOTE: GT/s indicates memory bus speed in Giga transfers per second.
• Performance Mode (2:1) up to 3.2 GT/s for higher bandwidth.
• Lock Step Mode (1:1) up to 1.87 GT/s for higher DDR4 speeds and better RAS (Reliability, Availability,
and Serviceability) features.
The maximum memory that is supported on your system varies according to the sizes of memory
modules being used. Single, dual, and quad rank DIMMs of capacities 8 GB, 16 GB, and 32 GB are
supported for a total of up to 3 TB.
NOTE: DIMMs in memory risers A and B are assigned to processor 1, C and D are assigned to
processor 2, E and F are assigned to processor 3 and G and H are assigned to processor 4.
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