Dell PowerEdge R7525 Installation and Service Manual

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System memory guidelines

The PowerEdgeR7525system supports DDR4 registered DIMMs (RDIMMs) and Load Reduced DIMM (LRDIMMs). System memory holds the instructions that are started by the processor.

Your system memory is organized into eight channels per processor (two memory sockets per channel),16 memory sockets per processor and 32 memory sockets per system.

This image shows Memory channels. — Figure 1. Memory channels

Memory channels are organized as follows:

Table 1. Memory channelsThe tables describe memory channels and how the channels are organized.
Processor	Channel A	Channel B	Channel C	Channel D	Channel E	Channel F	Channel G	Channel H
Processor 1	Slots A6 and A12	Slots A5 and A11	Slots A2 and A10	Slots A1 and A9	Slots A8 and A16	Slots A7 and A15	Slots A4 and A14	Slots A3 and A13
Processor 2	Slots B6 and B12	Slots B5 and B11	Slots B2 and B10	Slots B1 and B9	Slots B8 and B16	Slots B7 and B15	Slots B4 and B14	Slots B3 and B13

Table 2. Supported memory matrixThe table describes supported memory matrix.
DIMM type	Rank	Capacity	DIMM rated voltage and speed	Operating Speed on AMD EPYC™ processor
DIMM type	Rank	Capacity	DIMM rated voltage and speed	1 DIMM per channel (DPC)	2 DIMMs per channel (DPC)
RDIMM	1 R	8 GB	DDR4 (1.2 V), 3200 MT/s	3200 MT/s	2933 MT/s
RDIMM	2 R	16 GB, 32 GB, 64 GB	DDR4 (1.2 V), 3200 MT/s	3200 MT/s	2933 MT/s
LRDIMM	4 R	128 GB	DDR4 (1.2 V), 3200 MT/s	3200 MT/s	2933 MT/s
	8 R	128 GB	DDR4 (1.2 V), 2666 MT/s	2666 MT/s	2666 MT/s
	8 R	128 GB	DDR4 (1.2 V), 3200 MT/s	3200 MT/s	2933 MT/s

NOTE:The older 32 GB capacity RDIMM memory with x4 data width and 8Gb DRAM density cannot be mixed with the newer 32GB capacity RDIMM memory with x8 data width and 16Gb DRAM density in the same AMD EPYC™ processor unit.

NOTE:The older 128GB capacity LRDIMM memory at 2666 MT/s speed cannot be mixed with the new 128GB capacity LRDIMM memory at 3200 MT/s speed.