Lenovo System x3650 M4 HD, Installation And Service Manual

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• Blank = 1.5 V specified
• L = 1.35 V specified, 1.5 V operable
Note: Values for these voltages are “specified” which means the device characteristics such as
timing are supported at this voltage. Values are “operable” which means that the devices can
be operated safely at this voltage. However, device characteristics such as timing may not
be guaranteed. All devices must be “tolerant” of the highest DDR3 nominal voltage of 1.5 V,
meaning that they may not operate at 1.5 V but may be powered at that voltage without damage
to the devices.
– wwwww is the DIMM bandwidth, in MBps
6400 = 6.40 GBps (DDR3-800 SDRAMs, 8-byte primary data bus)
8500 = 8.53 GBps (DDR3-1066 SDRAMs, 8-byte primary data bus)
10600 = 10.66 GBps (DDR3-1333 SDRAMs, 8-byte primary data bus)
12800 = 12.80 GBps (DDR3-1600 SDRAMs, 8-byte primary data bus)
14900 = 14.93 GBps (DDR3-1866 SDRAMs, 8-byte primary data bus)
– m is the DIMM type
E = Unbuffered DIMM (UDIMM) with ECC (x72-bit module data bus)
L = Load Reduction DIMM (LRDIMM)
R = Registered DIMM (RDIMM)
U = Unbuffered DIMM with no ECC (x64-bit primary data bus)
– 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 n Rxxx 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).
• The following rules apply to DDR3 RDIMM speed as it relates to the number of RDIMMs in a channel:
– When you install 1 RDIMM per channel, the memory runs at 1866 MHz
– When you install 2 RDIMMs per channel, the memory runs at 1600 MHz
– When you install 3 RDIMMs per channel, the memory runs at 1066 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
• 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.
• 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 UDIMMs, 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 UDIMMs, RDIMMs or LRDIMMs will function at 1.5 V.
• The server supports a maximum of 16 dual-rank UDIMMs. The server supports up to two UDIMMs
per channel.
• The server supports a maximum of 24 single-rank, dual-rank, or 16 quad-rank RDIMMs. The server does
not support three quad-rank RDIMMs in the same channel.
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Lenovo System x3650 M4 HD Installation and Service Guide