Installing A Memory Module - IBM x3400 - System - 7975 User Manual

Installing a memory module

The following notes describe the types of dual inline memory modules (DIMMs) that
the server supports and other information that you must consider when installing
DIMMs:
v The server supports industry-standard, 1.8 V, 240-pin, 667 MHz, PC2-5300
v The DIMM options that are available for the server are 512 MB, 1 GB, and 2
v The system board provides 8 functional DIMM connectors and supports two-way
v The memory controller has four fully buffered DIMM channels that are organized
v The server can operate in two major modes: mirroring and non-mirroring
v The server supports memory mirroring (mirroring mode) and online-spare
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System x3400 Types 7973, 7974, 7975, and 7976: User's Guide
double-data-rate 2 (DDR2), dynamic random-access memory (DRAM) with error
correcting code (ECC), fully buffered dual inline memory modules (DIMMs).
These DIMMs must be compatible with the latest DDR2 667 MHz DRAM fully
buffered DIMM specification. For a list of supported options for the server, see
http://www.ibm.com/servers/eserver/serverproven/compat/us/; then, select your
country and navigate to the list of options for the server.
GB in x4 or x8 technology, single-rank or double-rank. The server supports a
minimum of 1 GB and a maximum of 32 GB (16 GB in mirrored mode) of system
memory. The server comes with two 512 MB DIMMs installed.
memory interleaving when DIMMs are installed in pairs. However, DIMM
connectors 3, 6, 9, and 12 are not functional. Do not install DIMMs in these four
connectors and do not remove the DIMM thermal baffles installed in these
connectors unless you need to replace the system board.
into two branches. Each branch has two channels, and each channel controls
two DIMMs. DIMMs that are next to each other (for example, DIMM slot 1 and
DIMM slot 4) within the channels of a branch must be identical in size, type,
speed, and technology. However, the DIMMs in the slots above or below each
other within the channels of a branch do not have to be identical (for example,
the DIMMs in DIMM slot 1 and DIMM slot 2 do not have to be identical). The
following illustration shows how the memory controller is organized into branches
and channels with two pairs of DIMMs installed.
DIMM 3
DIMM 2
DIMM 1
Channel 0 Channel 1
Branch 0
(normal). The server can also operate in a single-channel mode when one DIMM
is installed.
memory.
– Memory mirroring replicates and stores data on DIMMs within two branches
simultaneously. You must enable memory mirroring through the
Configuration/Setup Utility program (see "Using the Configuration/Setup Utility
program" on page 76). To enable memory mirroring in the Configuration/Setup
Utility program, select Devices and I/O Ports → Advanced Chipset Control →
Memory Branch Mode. Use the arrow keys to change the Memory Branch
Mode setting to Mirror; then, save your changes. When you use memory
mirroring, consider the following information:
DIMM 6 DIMM 9
DIMM 5 DIMM 8
DIMM 4 DIMM 7
Channel 2
Branch 1
Memory Controller
DIMM 12
DIMM 11
DIMM 10
Channel 3