IBM System x3650 M4 Type 7915 Installation And User Manual page 127

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.
v The server supports a maximum of 16 dual-rank UDIMMs. The server supports
up to two UDIMMs per channel.
v 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.
v The following table shows an example of the maximum amount of memory that
you can install using ranked DIMMs:
Table 7. Maximum memory installation using ranked DIMMs
Number of
DIMMs DIMM type
16 Dual-rank UDIMMs
24 Single-rank RDIMMs
24 Single-rank RDIMMs
24 Dual-rank RDIMMs
24 Dual-rank RDIMMs
24 Quad-rank HCDIMMs
16 Quad-rank RDIMMs
24 Quad-rank LRDIMMs
v 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.
v 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.
v The HCDIMM options that are available for the server are 16 GB and 32 GB.
The server supports a minimum of 16 GB and a maximum of 768 GB of system
memory using HCDIMMs.
Note: Do not mix the 16 GB HCDIMM and the 32 GB HCDIMM in the server.
v 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
Chapter 3, "Configuring the server," on page 141.
v 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.
v DIMMs in the server must be the same type (RDIMM, UDIMM, or LRDIMM) to
ensure that the server will operate correctly.
v When you install one quad-rank DIMM in a channel, install it in the DIMM
connector furthest away from the microprocessor.
DIMM size Total memory
4 GB 64 GB
2 GB 48 GB
4 GB 96 GB
8 GB 192 GB
16 GB 384 GB
32 GB 768 GB
16 GB 256 GB
32 GB 768 GB
Chapter 2. Installing optional devices
109