Dell EMC PowerEdge R7425 - General Memory Module Installation Guidelines; Mode-Specific Guidelines; Removing a Memory Module

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 cannot be mixed.
• Populate memory module sockets only if a processor is installed. For single-processor systems, sockets A1 to A16 are available. For dual-
pr
ocessor systems, sockets A1 to A16 and sockets B1 to B16 are available.
• Populate all the sockets with white release tabs r
st, followed by the 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er
ent capacities is not supported.
• Populate eight memory modules per processor (one DIMM per channel) at a time to maximize performance.
NOTE
: For optimal performance, it is recommended to populate one DIMM per channel with DDR4, 2666 MT/s memory modules
on the rst slot of each memory channel. The rst slot of each channel can be identied as the DIMM slots with white latches.
For example, 64 GB system memory capacity can be divided into 8 x 8 GB DIMM slots.
Mode-specic guidelines
Eight memory channels are allocated to each processor. The con
gurations allowed depend on the memory mode selected.
Memory optimized independent channel mode
This mode supports Single Device Data Correction (SDDC) only for memory modules that use x4 device width. It does not impose any
specic slot population requirements.
Table 44. Memory optimized (independent channel) mode
Processor Conguration Memory population rules Memory population
information
Single CPU Optimized (independent
channel) population
order
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
13, 14, 15, 16
Populate in this order,
odd amount of DIMMs
per CPU allowed.
Dual CPU (Starting with CPU1, CPU1 and CPU2
population should match)
Optimized (independent
channel) population
order
C1{1}, C2{1}, C1{2}, C2{2},
C1{3}, C2{3}…
Odd amount of DIMM
slots per CPU allowed.
Removing a memory module
Prerequisites
1 Follow the safety guidelines listed in Safety instructions.
2 Follow the procedure listed in Before working inside your system.
3 Remove the air shroud.
104 Installing and removing system components