The following rules apply when selecting the memory configuration:
The server supports RDIMMs and LRDIMMs.
Mixing different types of memory (RDIMMs and LRDIMMs) is not supported.
All DIMMs in the server operate at the same speed, which is determined as the lowest value of:
Memory speed that is supported by the specific processor.
Memory speed for selected quantity of DIMMs per channel.
The following memory protection technologies are supported:
ECC
Chipkill (for x4-based memory DIMMs)
Memory mirroring
Memory rank sparing
Chipkill works only in independent channel mode (the default operational mode) and supports only x4-based
memory DIMMs.
If memory mirroring is used, then DIMMs must be installed in pairs (a minimum of one pair per each processor),
and both DIMMs in a pair must be identical in type and size.
If memory rank sparing is used, then a minimum of one quad-rank DIMM or two single-rank or dual-rank
DIMMs must be installed per populated channel (the DIMMs do not need being identical). In rank sparing
mode, one rank of a DIMM in each populated channel is reserved as spare memory. The size of a rank varies
depending on the DIMMs installed.
Chipkill, memory mirroring, and memory rank sparing modes are mutually exclusive. Only one operational
memory mode can be enabled on a server, and it is a system-wide setting.
System x engineering tested and validated system designs that support memory speeds beyond Intel memory
specifications, which provides benefits for workloads that require memory speed and density. System x
TruDDR4 memory is fully supported up to the rated speeds that are shown in the following table.
Table 6. System x3650 M5 maximum memory speeds and capacities
DIMMs per channel
RDIMM
LR-DIMM
Memory bus speed
Maximum capacity*
Memory bus speed
Maximum capacity*
1 DPC
2400 MHz
256 GB (8x 32 GB)
2400 MHz
512 GB (8x 64 GB)
2 DPC
2400 MHz
512 GB (16x 32 GB)
2400 MHz
1,024 GB (16x 64 GB)
3 DPC
1866 MHz
768 GB (24x 32 GB)
2133 MHz
1,536 GB (24x 64 GB)
* Maximum memory capacity is achieved with two processors installed. With one processor, the maximum memory capacity is a
half of what is shown.
The following table lists memory options available for the System x3650 M5 server.
Table 7. Memory options
Description
Part
number
Feature
code
Maximum
supported*
RDIMMs - 2400 MHz
8GB TruDDR4 Memory (1Rx4, 1.2V) PC4-19200 CL17 2400MHz LP RDIMM
46W0821 ATC8
12 / 24
8GB TruDDR4 Memory (2Rx8, 1.2V) PC4-19200 CL17 2400MHz LP RDIMM
46W0825 ATC9
12 / 24
16GB TruDDR4 Memory (2Rx4, 1.2V) PC4-19200 CL17 2400MHz LP RDIMM
46W0829 ATCA
12 / 24
32GB TruDDR4 Memory (2Rx4, 1.2V) PC4-19200 CL17 2400MHz LP RDIMM
46W0833 ATCB
12 / 24
LRDIMMs - 2400 MHz
64GB TruDDR4 Memory (4Rx4, 1.2V) PC4-19200 PC4 2400MHz LP LRDIMM
46W0841 ATGG
12 / 24
* One processor / two processors
Lenovo System x3650 M5 (E5-2600 v4)
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