Table 7: DIMM Mixing Rules
DIMMs in the Same Bank
DIMMs in the Same Channel
DIMM Parameter
You cannot mix DIMM capacities in
a bank (for example A1, B1). Pairs of
DIMMs must be identical (same PID
and revision).
You can mix different capacity
DIMMs in the same channel (for
example, A1, A2).
DIMM Capacity
For example, 16GB,
32GB, 64GB, 128GB
You cannot mix DIMM speeds in a
bank (for example A1, B1). Pairs of
DIMMs must be identical (same PID
and revision).
You can mix speeds, but DIMMs
will run at the speed of the slowest
DIMMs/CPUs installed in the
channel.
DIMM speed
For example, 2666 GHz
You cannot mix DIMM types in a
bank.
You cannot mix DIMM types in a
channel.
DIMM type
RDIMMs or LRDIMMs
Memory Mirroring
The Intel CPUs within the server support memory mirroring only when an even number of channels are
populated with DIMMs. If one or three channels are populated with DIMMs, memory mirroring is automatically
disabled.
Memory mirroring reduces the amount of memory available by 50 percent because only one of the two
populated channels provides data. The second, duplicate channel provides redundancy.
Replacing DIMMs
Identifying a Faulty DIMM
Each DIMM socket has a corresponding DIMM fault LED, directly in front of the DIMM socket. See
for the locations of these LEDs.
Step 1
Caution
Never remove a CPU module without shutting down and removing power from the server.
Prepare the server for component removal:
a) Shut down and remove power from the server as described in
Shutting Down and Removing Power From the Server,
.
You do not have to pull the server out of the rack or remove the server cover because the CPU modules
are accessible from the front of the server.
Note
Step 2
Remove an existing CPU module from the chassis:
Verify that the power LED on the front of the CPU module is off before removing the module.
Note
a) Grasp the two ejector levers on the front of the CPU module and pinch their latches to release the levers.
b) Rotate both levers to the outside at the same time to evenly disengage the module from the midplane connectors.
c) Pull the module straight out from the chassis and then set it on an antistatic surface.
Step 3
Remove an existing DIMM (or DIMM blank) from the CPU module:
Maintaining the Server
84
Maintaining the Server
Replacing DIMMs
