Removing A Memory Module - Dell EMC PowerEdge R940 Installation And Service Manual

used to mirror the active memory modules. In the event of an uncorrectable error, the system switches over to the mirrored copy. This
ensures Single Device Data Correction (SDDC) and multi-bit protection.
The installation guidelines for memory modules are as follows:
• Memory modules must be identical in size, speed, and technology.
• Memory modules must be populated in sets of 6 per CPU to enable memory mirroring.
Table 40. Memory population rules
Processor Configuration
Dual CPU (Start with Optimized (Independent channel)
CPU1. CPU1 and CPU2 population order
population should
Mirroring population order
match)
Single rank sparing population order C1{1}, C2{1}, C1{2}, C2{2}, C1{3},
Multi rank spare population order
Fault resilient population order
Quad CPU (Start with Optimized (Independent channel)
CPU1. CPU1, CPU2, population order
CPU3, and CPU4
Mirroring population order
population should
match)
Single rank sparing population order C1{1},C2{1},C3{1},C4{1},C1{2},C
Multi rank spare population order
Fault resilient population order

Removing a memory module

Prerequisites
1 Follow the safety guidelines listed in
2 Follow the procedure listed in
3 If applicable, remove the air shroud.
WARNING: Allow the memory modules to cool after you power off the system. Handle the memory modules by the card edges
and avoid touching the components or metallic contacts on the memory module.
CAUTION: To ensure proper system cooling, memory module blanks must be installed in any memory socket that is not occupied.
Remove memory module blanks only if you intend to install memory modules in those sockets.
Safety instructions.
Before working inside your
Memory population
C1{1}, C2{1}, C1{2}, C2{2}, C1{3},
C2{3}...
C1{1, 2, 3, 4, 5, 6}, C2{1, 2, 3, 4, 5,
6}, C1{7, 8, 9, 10, 11, 12}, C2{7, 8,
9, 10, 11, 12}
C2{3}...
C1{1}, C2{1}, C1{2}, C2{2}, C1{3},
C2{3}, C1{4}, C2{4}, C1{5},
C2{5}...
C1{1, 2, 3, 4, 5, 6}, C2{1, 2, 3, 4, 5,
6}, C1{7, 8, 9, 10, 11, 12}, C2{7, 8,
9, 10, 11, 12}
C1{1},C2{1},C3{1},C4{1},C1{2},C
2{2},C3{2},C4{2}...
C1{1,2,3,4,5,6},C2{1,2,3,4,5,6},C3{
1,2,3,4,5,6},C4{1,2,3,4,5,6}...
2{2},C3{2},C4{2}...
C1{1},C2{1},C3{1},C4{1},C1{2},C
2{2},C3{2},C4{2}...
C1{1,2,3,4,5,6},C2{1,2,3,4,5,6},C3{
1,2,3,4,5,6},C4{1,2,3,4,5,6}...
system.
Installing and removing system components
Memory population information
Odd amount of DIMMs per CPU
allowed.
Mirroring is supported with 6 or 12
DIMMs per CPU.
Populate in this order, odd amount per
CPU allowed. Requires two ranks or
more per channel.
Populate in this order, odd amount per
CPU allowed. Requires three ranks or
more per channel.
Supported with 6 or 12 DIMMs per
CPU.
Odd amount of DIMMs per CPU
allowed.
Mirroring is supported with 6 or 12
DIMMs per CPU.
Populate in this order, odd amount per
CPU allowed. Requires two ranks or
more per channel.
Populate in this order, odd amount per
CPU allowed. Requires three ranks or
more per channel.
Supported with 6 or 12 DIMMs per
CPU.
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