Lenovo System x3550 M4 Installation And Service Manual page 233

– 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.
• The server supports a maximum of 16 dual-rank UDIMMs. The server supports up to two UDIMMs per
channel.
• The server supports a maximum of 24 single-rank, dual-rank, or 16 quad-rank RDIMMs. The server does
not support three quad-rank RDIMMs in the same channel.
• The following table shows an example of the maximum amount of memory that you can install using
ranked DIMMs:
Table 20. Maximum memory installation using ranked DIMMs
Number of DIMMs
16
24
24
24
24
24
16
24
• The UDIMM option that is available for the server is 4 GB. The server supports a minimum of 4 GB and a
maximum of 64 GB of system memory using UDIMMs.
• The RDIMM options that are available for the server are 2 GB, 4 GB, 8 GB, and 16 GB. The server
supports a minimum of 2 GB and a maximum of 384 GB of system memory using RDIMMs.
• The LRDIMM option that is available for the server is 32 GB. The server supports a minimum of 32 GB and
a maximum of 768 GB of system memory using LRDIMMs.
Note: 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 92.
• A minimum of one DIMM must be installed for each microprocessor. For example, you must install a
minimum of two DIMMs if the server has two microprocessors installed. However, to improve system
performance, install a minimum of four DIMMs for each microprocessor.
• DIMMs in the server must be the same type (RDIMM, UDIMM, or LRDIMM) to ensure that the server will
operate correctly.
• When you install one quad-rank DIMM in a channel, install it in the DIMM connector furthest away from the
microprocessor.
Notes:
1. You can install DIMMs for microprocessor 2 as soon as you install microprocessor 2; you do not have to
wait until all of the DIMM slots for microprocessor 1 are filled.
2. DIMM slots 13-24 are reserved for microprocessor 2; thus, DIMM slots 13-24 are enabled when
microprocessor 2 is installed.
The following illustration shows the location of the DIMM connectors on the system board.
DIMM type
Dual-rank UDIMM
Single-rank RDIMM
Single-rank RDIMM
Dual-rank RDIMM
Dual-rank RDIMM
Dual-rank RDIMM
Quad-rank RDIMM
Quad-rank LRDIMM
DIMM size
4 GB
2 GB
4 GB
4 GB
8 GB
16 GB
8 GB
32 GB
.
Chapter 6 Removing and replacing components
Total memory
64 GB
48 GB
96 GB
96 GB
192 GB
384 GB
128 GB
768 GB
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