General Memory Module Installation Guidelines; Removing A Memory Module - Dell PowerEdge R7725 Installation And Service Manual

General memory module installation guidelines

To ensure optimal performance of your system, observe the following general guidelines when configuring your system memory.
If your system's memory configuration fails to observe these guidelines, your system might not boot, stop responding during
memory configuration, or operate with reduced memory.
The memory bus may operate at speeds of 6000 MT/s or lower depending on the following factors:
● System profile selected (for example, Performance, Performance Per Watt Optimized (OS), or Custom [can be run at high
speed or lower])
● Maximum supported DIMM speed of the processors
● Maximum supported speed of the DIMMs
NOTE: MT/s indicates DIMM speed in Mega-Transfers per second.
The following are the recommended guidelines for installing memory modules:
● All DIMMs must be DDR5.
● DIMM mixing configurations are not supported. All DIMM slots must be populated with the exact same DIMMs.
● Populate memory module sockets only if a processor is installed.
○ A minimum of one DIMM must be populated for each installed processor.
● In Optimizer Mode, the DRAM controllers operate independently in the 64-bit mode and provide optimized memory
performance.
Table 44. Memory population rules
Processor
Dual processor (Start
with processor 1.
Processor 1 and
processor 2 population
should match)
● In a dual-processor configuration, the memory configuration for each processor must be identical. For example, if you
populate socket A1 for processor 1, then populate socket B1 for processor 2, and so on.
● Unbalanced or odd memory configurations result in a performance loss, and the system may not identify the memory
modules being installed. Always populate memory channels identically with equal DIMMs for the best performance.
● For best performance, populate all memory channels equally (12 DIMMs per CPU) using identical DIMMs.
● Mixing of any different memory module capacities is not supported.
● Mixing module types within a memory channel is not supported. All DIMMs populated must be RDIMM.
● Mixing different widths (x4 and x8) is not supported.
NOTE: If memory modules with different speeds are installed, they operate at the speed of the slowest installed memory
module(s).

Removing a memory module

Prerequisites
1. Follow the safety guidelines listed in the
2. Follow the procedure listed in
3. Remove the air shroud.
WARNING: The memory modules are hot to touch for some time after the system has been powered off. Allow
the memory modules to cool before handling them.
NOTE: For proper system cooling, DIMM blanks must be installed in any memory socket that is not populated, only if the
processor TDP is greater than 250 W. Remove the memory module blanks only if you intend to install the memory module in
these sockets.
Steps
1. Locate the appropriate memory module socket.
Memory population
A{1}, B{1}, A{2}, B{2}, A{3}, B{3}, A{4}, B{4}, A{5}, B{5}, A{6}, B{6},
A{7}, B{7} A{8}, B{8}, A{9}, B{9}, A{10}, B{10}, A{11}, B{11}, A{12}, B{12},
Safety instructions.
Before working inside your system.
Installing and removing system components
Memory population
information
1, 2, 4, 6, 8, 10, 12
DIMMs are allowed.
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