Lenovo NeXtScale nx360 M5, Installation And Service Manual, Page: 170 / 1022

– When you install 1 LRDIMM per channel, the memory runs at 2133 MHz
– When you install 2 LRDIMMs per channel, the memory runs at 2133 MHz
– All channels in a server run at the fastest common frequency
– Do not install registered and load reduction DIMMs in the same server
• The maximum memory speed is determined by the combination of the microprocessor, DIMM speed,
DIMM type, Operating Modes in UEFI settings, and the number of DIMMs installed in each channel.
• In two-DIMM-per-channel configuration, the compute node automatically operates with 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 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 compute node supports a maximum of 16 single-rank, dual--rank RDIMMs or 16 quad-rank LRIMMs.
• The following table shows an example of the maximum amount of memory that you can install using
ranked DIMMs:
Table 10. Maximum memory installation using ranked DIMMs
Number of DIMMs DIMM type DIMM size Total memory
16 Single-rank RDIMM 4 GB 64 GB
16 Single-rank RDIMM 8 GB 128 GB
16 Dual-rank RDIMM
8 GB 128 GB
16 Dual-rank RDIMM 16 GB 256 GB
16 Quad-rank LRDIMM 32 GB 512 GB
• The RDIMM options that are available for the compute node are 4 GB, 8 GB, and 16 GB. The compute
node supports a minimum of 4 GB and a maximum of 256 GB of system memory using RDIMMs.
• The LRDIMM option that is available for the server is 32 GB. The compute node supports a minimum of
32 GB and a maximum of 512 GB of system memory using LRDIMMs
• A minimum of one DIMM must be installed for each microprocessor. For example, you must install a
minimum of two DIMMs if the compute node has two microprocessors installed. However, to improve
system performance, install a minimum of four DIMMs for each microprocessor.
• DIMMs in the compute node must be the same type to ensure that the compute node 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 9-16 are reserved for microprocessor 2; thus, DIMM slots 9-16 are enabled when
microprocessor 2 is installed.
The following illustration shows the location of the DIMM connectors on the system board.
156
Lenovo NeXtScale nx360 M5 Installation and Service Guide