IBM 8649 - Eserver xSeries 225, Maintenance And Troubleshooting Manual

Page: 65 / 194

the maximum cable length that supports Ultra320 SCSI hard disk drives is 16
inches. For more information about connecting SCSI devices, see the SCSI
documentation.
Installing memory modules
You can increase the amount of memory in your server by installing memory
modules. Your server uses industry-standard PC2100 double-data-rate (DDR) dual
inline memory modules (DIMMs).
Notes:
1. The system board contains four DIMM connectors and supports two-way
memory interleaving.
2. The DIMM options available for your server are 128 MB, 256 MB, 512 MB, 1
GB, and 2 GB. Your server supports a minimum of 256 MB and a maximum of 8
GB of system memory.
3. The amount of usable memory will be reduced depending on the system
configuration. A certain amount of memory must be reserved for system
resources. The BIOS will display the total amount of installed memory and the
amount of configured memory.
4. Your server comes with two 256 MB or 512 MB DIMMs (for a total of 512 MB or
1024 MB) installed in the DIMM 3 and DIMM 4 memory connectors. When you
install additional DIMMs, be sure to install them as a pair in DIMM connectors 1
and 2.
5. DIMMs must be installed in matched pairs. The first pair of DIMMs you install in
DIMM 3 and DIMM 4 memory connectors must be the same size, speed, type,
and technology. You can mix compatible DIMMs from various manufacturers. If
you install a second pair of DIMMs in DIMM 1 and DIMM 2 memory connectors,
they do not have to be the same size, speed, type, and technology as the
DIMMs you installed in DIMM 3 and DIMM 4 memory connectors. However, the
size, speed, type, and technology of the DIMMs you install in DIMM 1 and
DIMM 2 memory connectors must match each other.
6. Install only 133 MHz (memory bus), 2.5 V, 184-pin, double-data-rate (DDR),
PC2100, registered synchronous dynamic random-access memory (SDRAM)
with error correcting code (ECC) DIMMs. These DIMMs must be compatible
with the latest PC2100 SDRAM Registered DIMM specification. For a list of
supported options for your server, go to http://www.ibm.com/servers/eserver/
serverproven/compat/us/ on the World Wide Web.
7. Your server supports Chipkill
™
memory if the DIMMs are all type x4 and are 512
MB or larger. Your server also supports Chipkill memory if two 256 MB DIMMs
and two 512 MB DIMMs are installed; however, only the 512 MB DIMMs provide
Chipkill memory support. All 128 MB DIMMs, 256 MB DIMMs, or DIMMs that
are not type x4 do not provide Chipkill memory support.
Complete the following steps to install a DIMM:
1. Review the safety information beginning on page 129 “Installation guidelines”
on page 33, and “Handling static-sensitive devices” on page 34.
2. Turn off the server and disconnect all power cords and external cables; then,
remove the side cover (see “Removing the side cover” on page 36).
3. Remove the support bracket (see “Removing and installing the support
bracket” on page 38).
4. Locate the DIMM connectors on the system board. Determine the connectors
into which you will install the DIMMs. Install the DIMMs in the order shown in
the following table.
Chapter 4. Installing options
55