Lenovo System x3650 M5 Installation And Service Manual page 196

where:
– ggggg is the total capacity of the DIMM (for example, 1GB, 2GB, or 4GB)
– eR is the number of ranks
1R = single-rank
2R = dual-rank
4R = quad-rank
– xff is the device organization (bit width)
x4 = x4 organization (4 DQ lines per SDRAM)
x8 = x8 organization
x16 = x16 organization
– v is the SDRAM and support component supply voltage (VDD)
• 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)
19200 = 19.20 Gbps (DDR4-2400 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).
• The following rules apply to 2400 MHz 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 2400 MHz
– When you install 2 RDIMMs per channel, the memory runs at 2400 MHz
– When you install 3 RDIMMs per channel, the memory runs at 1866 MHz
– All channels in a server run at the fastest common frequency
– Do not install registered and load reduction DIMMs in the same server
• The following rules apply to 2400 MHz DDR4 LRDIMM speed as it relates to the number of LRDIMMs in a
channel:
– When you install 1 LRDIMM per channel, the memory runs at 2400 MHz
– When you install 2 LRDIMMs per channel, the memory runs at 2400 MHz
– When you install 3 LRDIMMs per channel, the memory runs at 2133 MHz
• 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.
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Lenovo System x3650 M5 Installation and Service Guide