IBM System x3100 M4 Type 2582 Problem Determination And Service Manual page 224

Unbuffered DIMMs (UDIMMs)
The following notes provide information that you must consider when you install
UDIMMs:
v The memory channels run at the lowest common frequency of the DIMMs
v The UDIMM options that are available for the server are 1 GB, 2 GB, 4 GB, and
v The server supports up to two single-rank or dual-rank UDIMMs per channel.
v The following table lists the supported UDIMM population.
v The following table lists the maximum DIMM population using ranked UDIMMs.
v The following table shows the UDIMM memory population rule to optimize the
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IBM System x3100 M4 Type 2582: Problem Determination and Service Guide
12800 = 12.8 GBps (PC3-1600 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
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 PC3-xxxxx-xx-xx-xxx. The
numeral in the sixth numerical position indicates whether the DIMM is single-rank
(n=1) or dual-rank (n=2).
installed.
8 GB (when available) DIMMs.
Table 14. Supported UDIMM population per channel
DIMM
connectors per DIMMs installed
channel in each channel DIMM type
2 1
2 2
Table 15. Maximum memory population using ranked UDIMMs (depending on your model)
Number of UDIMMs DIMM type
4 Single-rank UDIMMs
4 Dual-rank UDIMMs
4 Dual-rank UDIMMs
4 Dual-rank UDIMMs
system performance.
Table 16. UDIMM population rule
DIMM connector 1 DIMM connector 2
Populated Empty
DIMM speed
Unbuffered 1066, 1333,
DDR3 ECC 1600
Unbuffered 1066, 1333,
DDR3 ECC 1600
Size
1 GB
2 GB
4 GB
8 GB (when
available)
DIMM connector 3
Empty
Ranks per
DIMM (any
combination)
Single-rank,
dual-rank
Single-rank,
dual-rank
Total memory
4 GB
8 GB
16 GB
32 GB
DIMM connector 4
Empty