Lenovo System x3550 M4 Installation And Service Manual page 60

– ggggg is the total capacity of the DIMM (for example, 1 GB, 2 GB, or 4 GB)
– 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 = 1.5 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 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).
• 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
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Lenovo System x3550 M4 Installation and Service Guide