v Blank = 1.2 V specified
- wwwww is the DIMM bandwidth, in MBps
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 PC3v-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).
v The following rules apply to DDR4 RDIMM speed as it relates to the number of
RDIMMs in a channel:
– When you install 1 RDIMM per channel, the memory runs at 1600 MHz
– When you install 2 RDIMMs per channel, the memory runs at 1860 MHz
– When you install 3 RDIMMs per channel, the memory runs at 2133 MHz
– All channels in a server run at the fastest common frequency
– Do not install registered, unbuffered, and load reduction DIMMs in the same
server
v The maximum memory speed is determined by the combination of the
microprocessor, DIMM speed, DIMM type, Operating Modes in UEFI settings,
and the number of DIMMs installed in each channel.
v In two-DIMM-per-channel configuration, the server automatically operates with
a maximum memory speed of up to 1600 MHz when the following condition is
met:
– Two 1.35 V single-rank, dual-ranl, or quad-rank RDIMMs or LRDIMMs are
installed in the same channel. In the Setup utility, Memory speed is set to
Max performance and LV-DIMM power is set to Enhance performance
mode. The 1.35 V RDIMMs or LRDIMMs will function at 1.5 V.
v The server supports a maximum of 24 single-rank, dual-rank RDIMMs or 24
quad-rank LRIMMs.
v The following table shows an example of the maximum amount of memory that
you can install using ranked DIMMs or load-reduced DIMMs:
Table 24. Maximum memory installation
Number of DIMMs DIMM type Size Total memory
24 Single-rank RDIMM 4 GB 96 GB
24 Dual-rank RDIMM 8 GB 192 GB
24 Dual-rank RDIMM 16 GB 384 GB
16 Quad-rank LRDIMM 32 GB 768 GB
24 Quad-rank LRDIMM 64 GB 1536 GB
166 IBM System x3550 M5 Type 5463: Installation and Service Guide
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