Lenovo System x3250 M4, Installation And Service Manual

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– eR is the number of ranks
– 1R = single-rank
– 2R = dual-rank
– 4R = quad-rank
– xf is the device organization or bit width (for example, x4, x8, or x16)
– x4 = x4 organization (4 DQ lines per SDRAM)
– x8 = x8 organization
– x16 = x16 organization
– wwwww is the DIMM bandwidth, in MBps
• 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)
– m is the DIMM type
• E = Unbuffered DIMM (UDIMM) with ECC (x72-bit module data bus)
• 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
Notes:
1. To determine the type of a DIMM, see the label on the DIMM. The information on the label is in the
format xGB nRxx PC3v-xxxxxx-xx-xx-xx. The numeral in the sixth numerical position indicates
whether the DIMM is single-rank (n=1) or dual-rank (n=2).
2. The amount of usable memory is reduced, depending on the system configuration. A certain
amount of memory must be reserved for system resources. To view the total amount of installed
memory and the amount of configured memory, run the Setup utility. For additional information, see
“Configuring the server” on page 62.
Unbuffered DIMMs (UDIMMs)
The following notes provide information that you must consider when you install UDIMMs.
• The memory channels run at the lowest common frequency of the DIMMs installed.
• The UDIMM options that are available for the server are 1 GB, 2 GB, 4 GB, and 8 GB (when available)
DIMMs.
• The server supports up to two single-rank or dual-rank UDIMMs per channel.
• The following table lists the supported UDIMM population.
Table 31. Supported UDIMM population per channel
DIMM connectors
per channel DIMMs installed in
each channel
DIMM type DIMM speed
Ranks per DIMM
(any combination)
2 1 Unbuffered DDR3
ECC 1066, 1333, 1600
Single-rank,
dual-rank
2 2 Unbuffered DDR3
ECC 1066, 1333, 1600 Single-rank,
dual-rank
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Lenovo System x3250 M4 Installation and Service Guide