Installing A Memory Module - IBM 84885BU Maintenance And Troubleshooting 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 comes with either two 256 MB or two 512 MB memory DIMMs
v DIMMs must be installed in matched pairs. The DIMMs in each pair must be the
v Install only 1.8 V, 184-pin, double-data-rate 2 (DDR2), PC2-3200, registered,
v The system board contains six DIMM connectors and supports two-way memory
v The DIMM-installation sequence is based on single-rank DIMMs, double-rank
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xSeries 226 Type 8488 and 8648: Hardware Maintenance Manual and Troubleshooting Guide
installed in DIMM 1 and DIMM 2 memory connectors. The second pair of DIMMs
must be installed in DIMM 3 and DIMM 4 memory connectors and the third pair
in DIMM 5 and DIMM 6 memory connectors.
same size, speed, type, and technology as each other but do not have to match
the other pairs. You can mix compatible DIMMs from various manufacturers.
synchronous dynamic random-access memory (SDRAM) with error correcting
code (ECC), dual inline memory modules (DIMMs). These DIMMs must be
compatible with the latest PC2-3200 SDRAM buffered DIMM specification. For a
list of supported options for the server, go to http://www.ibm.com/pc/; then, select
your country and navigate to the list of options for the server.
interleaving when the DIMMs are installed in pairs and functioning properly. If
one DIMM in the pair fails, the server runs in single-channel mode
(non-interleaving). A failed DIMM must be replaced as soon as possible;
otherwise, the server will not start (boot).
DIMMs, and mixing single-rank and double-rank DIMMs. Single-rank DIMMs are
256 MB, 512 MB, and 1 GB memory modules. Double-rank DIMMs are 2 GB
memory modules. The following table lists the DIMM-installation sequence for the
server maximum memory capacity using mixed single-rank and double-rank
DIMMs.
Notes:
1. Do not install four 2 GB double-rank DIMMs for the server maximum capacity
(8 GB) configuration; the server does not support it.
2. You can install pairs of 256 MB, 512 MB, 1 GB, and 2 GB DIMMs in the
server, but for the server maximum capacity you must use the
DIMM-sequence in the table below.
3. You can install any combination of DIMM pairs in the server; however, you
can install only two 2 GB double-rank DIMMs in the server, and they must go
in DIMM connectors 1 and 2. Do not install 2 GB double-rank DIMMs in any
connectors other than DIMM connectors 1 and 2.
4. If you order DIMMs from IBM, the variable 2R in the description for the
memory indicates that the DIMM is a double-rank 2 GB DIMM.
Table 2. Maximum memory capacity (8 GB) and installation sequence mixing single-rank
and double-rank DIMMs
DIMM pair DIMM connectors
First pair
Second pair
Third pair
DIMM size
1, 2 2 GB
3, 4 1 GB
5, 6 1 GB
Rank
Double-rank
Single-rank
Single-rank