IBM System x3650 M5 Installation And Service Manual page 184

v The following rules apply to DDR4 RDIMM speed as it relates to the number of
v The following rules apply to DDR4 RDIMM speed as it relates to the number of
v The maximum memory speed is determined by the combination of the
v The server supports a maximum of 24 single-rank, dual-rank RDIMMs or 24
v The following table shows an example of the maximum amount of memory that
v The RDIMM options that are available for the server are 4 GB, 8 GB, and 16 GB.
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System x3650 M5 Type 5462: Installation and Service Guide
12800 = 12.80 GBps (DDR4-1600 SDRAMs, 8-byte primary data bus)
14900 = 14.93 GBps (DDR4-1866 SDRAMs, 8-byte primary data bus)
17000 = 17.00 GBps (DDR4-2133 SDRAMs, 8-byte primary data bus)
- m is the DIMM type
L = Load Reduction DIMM (LRDIMM)
R = Registered DIMM (RDIMM)
- aa is the CAS latency, in clocks at maximum operating frequency
- bb is the JEDEC SPD Revision Encoding and Additions level
- cc is the reference design file for the design of the DIMM
- d is the revision number of the reference design of the DIMM
Note: To determine the type of a DIMM, see the label on the DIMM. The
information on the label is in the format xxxxx nRxxx PC4v-xxxxxx-xx-xx-xxx.
The numeral in the sixth numerical position indicates whether the DIMM is
single-rank (n=1), dual-rank (n=2), or quad-rank (n=4).
RDIMMs in a channel:
– When you install 1 RDIMM per channel, the memory runs at 2133 MHz
– When you install 2 RDIMMs per channel, the memory runs at 1866 MHz
– When you install 3 RDIMMs per channel, the memory runs at 1600 MHz
– All channels in a server run at the fastest common frequency
– Do not install registered and load reduction DIMMs in the same server
LRDIMMs in a channel:
– When you install 1 LRDIMM per channel, the memory runs at 2133MHz
– When you install 2 LRDIMMs per channel, the memory runs at 2133 MHz
– When you install 3 LRDIMMs per channel, the memory runs at 1600 MHz
microprocessor, DIMM speed, DIMM type, Operating Modes in UEFI settings,
and the number of DIMMs installed in each channel.
quad-rank LRIMMs.
you can install using ranked DIMMs:
Table 10. Maximum memory installation using ranked DIMMs
Number of
DIMMs DIMM type
24 Single-rank RDIMMs
24 Dual-rank RDIMMs
24 Dual-rank RDIMMs
24 Quad-rank LRDIMMs
24 Quad-rank LRDIMMs
The server supports a minimum of 4 GB and a maximum of 384 GB of system
memory using RDIMMs.
DIMM size Total memory
4 GB 96 GB
8 GB 192 GB
16 GB 384 GB
32 GB 768 GB
64 GB 1536 GB