IBM 7979B1U User Manual page 84

v Each DIMM in a pair must be the same size, speed, type, and technology to
v You can configure the server to use memory mirroring. Memory mirroring stores
v The server supports online-spare memory. This feature disables the failed
v You can enable either online-spare memory or memory mirroring, but not both at
v When you install or remove DIMMs, the server configuration information
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System x3650 Type 7979: User's Guide
Note: When only one pair of DIMMs is installed in the server and the BIOS code
level is version 1.04 (GGE127A) or later, you can improve performance by
installing the DIMMs in connectors 1 and 7 instead of 1 and 4. However, because
the connectors in the pair are not on the same memory branch (see the following
illustration), Chipkill memory protection is disabled.
ensure that the server will operate correctly.
data in two pairs of DIMMs simultaneously. If a failure occurs, the memory
controller switches from the active pair to the mirroring pair. See "Memory
mirroring" on page 69 for more information about memory mirroring and the
DIMM installation sequence that is required.
memory from the system configuration and activates an online-spare pair of
DIMMs to replace the failed active DIMM pair. See "Online-spare memory" on
page 70 for more information about online-spare memory and the DIMM
configuration that is required.
the same time. Online-spare memory provides more memory capacity than
mirroring. Mirroring provides better memory protection but less memory capacity
than online-spare memory.
changes. When you restart the server, the system displays a message that
indicates that the memory configuration has changed.
DIMM 12
Channel 3
DIMM 11
DIMM 10
Branch 1
DIMM 9
DIMM 8
Channel 2
DIMM 7
DIMM 6
Channel 1
DIMM 5
DIMM 4
Branch 0
DIMM 3
Channel 0
DIMM 2
DIMM 1