IBM x3630 M3 7377, Problem Determination And Service Manual

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– When you install two 1.35 V DIMMs in a channel, the memory runs at 800
MHz. The DIMMs still function at 1.35 V
– When you install quad-rank DIMMs with single-rank or dual-rank DIMMs in the
same channel, the memory runs at 800 MHz
– All channels in a server run at the fastest common frequency
v
In two-DIMM-per-channel configuration, a server with an Intel Xeon X5600 series
microprocessor automatically operates with a maximum memory speed of up to
1333 MHz when one of the following conditions is met:
– Two 1.5 V single-rank or dual-rank RDIMMs are installed in the same channel.
In the Setup utility, Memory speed is set to Max performance mode
– Two 1.35 V single-rank or dual-ranl RDIMMs 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 RDIMMs
will function at 1.5 V
v The server supports a maximum of 12 single-rank or dual-rank registered DIMMs
(RDIMMs).
v
The server supports three single-rank or dual-rank DIMMs per channel. The
following table shows an example of the maximum amount of memory that you
can install, using ranked RDIMMs.
Table 10. Maximum memory installation using ranked RDIMMs
DIMM type
Maximum number
of DIMMs
DIMM size Total memory
Single-rank 12 1 GB 12 GB
Singe-rank 12 2 GB 24 GB
Dual-rank 12 2 GB 24 GB
Dual-rank 12 4 GB 48 GB
Dual-rank 12 8 GB 96 GB
v The RDIMM options that are available for the server are 1 GB, 2 GB, 4 GB, and
8 GB. The server supports a minimum of 1 GB and a maximum of 96 GB of
system memory.
For 32-bit operating systems only: Some memory is reserved for various
system resources and is unavailable to the operating system. The amount of
memory that is reserved for system resources depends on the operating system,
the configuration of the server, and the configured PCI devices. To view the total
amount of installed memory and the amount of configured memory, run the Setup
utility. For additional information, see “Using the Setup utility” on page 235.
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. However, to improve system performance, install a minimum of
three DIMMs for each microprocessor.
Note: 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 connectors for
microprocessor 1 are filled.
v
When you install one quad-rank RDIMM in a channel, install it in the DIMM
connector furthest away from the microprocessor.
v Always install the highest-ranked DIMM in the DIMM connector furthest away
from the microprocessor. For example, if you are installing a single-rank,
Chapter 5. Removing and replacing server components
163