IBM NeXtScale nx360 M4 Installation And Service Manual page 152

v The following rules apply to DDR3 RDIMM speed as it relates to the number of
v The maximum memory speed is determined by the combination of the
v In two-DIMM-per-channel configuration, the compute node automatically
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IBM NeXtScale nx360 M4 Type 5455: Installation and Service Guide
x8 = x8 organization
x16 = x16 organization
- v is the SDRAM and support component supply voltage (VDD)
v Blank = 1.5 V specified
v 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 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).
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 compute node run at the fastest common frequency
– Do not install registered, unbuffered, and load reduction DIMMs in the same
compute node
microprocessor, DIMM speed, DIMM type, Operating Modes in UEFI settings,
and the number of DIMMs installed in each channel.
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