IBM System x3550 M4 Installation And Service Manual page 256

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 server automatically operates with
v The server supports a maximum of 16 dual-rank UDIMMs. The server supports
v The server supports a maximum of 24 single-rank, dual-rank, or 16 quad-rank
v The following table shows an example of the maximum amount of memory that
v The UDIMM option that is available for the server is 4 GB. The server supports
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IBM System x3550 M4 Type 7914: Installation and Service Guide
- 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 server run at the fastest common frequency
– Do not install registered, unbuffered, and load reduction DIMMs in the same
server
microprocessor, DIMM speed, DIMM type, Operating Modes in UEFI settings,
and the number of DIMMs installed in each channel.
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.
up to two UDIMMs per channel.
RDIMMs. The server does not support three quad-rank RDIMMs in the same
channel.
you can install using ranked DIMMs:
Table 20. Maximum memory installation using ranked DIMMs
Number of
DIMMs DIMM type
16 Dual-rank UDIMM
24 Single-rank RDIMM
24 Single-rank RDIMM
24 Dual-rank RDIMM
24 Dual-rank RDIMM
24 Dual-rank RDIMM
16 Quad-rank RDIMM
24 Quad-rank LRDIMM
a minimum of 4 GB and a maximum of 64 GB of system memory using
UDIMMs.
DIMM size Total memory
4 GB 64 GB
2 GB 48 GB
4 GB 96 GB
4 GB 96 GB
8 GB 192 GB
16 GB 384 GB
8 GB 128 GB
32 GB 768 GB