Cisco UCS C240 M5 Service Manual

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Each channel has two DIMM sockets (for example, channel A = slots A1, A2).
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A channel can operate with one or two DIMMs installed.
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If a channel has only one DIMM, populate slot 1 first (the blue slot).
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When both CPUs are installed, populate the DIMM sockets of each CPU identically.
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Fill blue #1 slots in the channels first: A1, G1, B1, H1, C1, J1, D1, K1, E1, L1, F1, M1
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Fill black #2 slots in the channels second: A2, G2, B2, H2, C2, J2, D2, K2, E2, L2, F2, M2
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Any DIMM installed in a DIMM socket for which the CPU is absent is not recognized. In a single-CPU
configuration, populate the channels for CPU1 only (A, B, C, D, E, F).
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The maximum combined memory allowed in the 12 DIMM slots controlled by any one CPU is 768 GB.
To populate the 12 DIMM slots with more than 768 GB of combined memory, you must use a
high-memory CPU that has a PID that ends with an "M", for example, UCS-CPU-6134M.
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Memory mirroring reduces the amount of memory available by 50 percent because only one of the two
populated channels provides data. When memory mirroring is enabled, you must install DIMMs in even
numbers of channels.
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The NVIDIA Tesla P-Series GPU can support more than 1 TB of memory in the server. All other
NVIDIA GPUs can support only 1 TB or less of memory in the server. Therefore, do not install DIMMs
totalling more than 1 TB capacity when using an NVIDIA GPU card other than P-Series in this server.
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Observe the DIMM mixing rules shown in the following table.
Table 4: DIMM Mixing Rules
DIMMs in the Same BankDIMMs in the Same ChannelDIMM 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, 8GB, 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 CPUs in 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.
Cisco UCS C240 M5 Server Installation and Service Guide
71
Maintaining the Server
Replacing Memory DIMMs

Cisco UCS C240 M5 Specifications

General

Form Factor	2U Rack
Storage Controllers	Cisco 12G SAS Modular RAID Controller
Management	Cisco Integrated Management Controller (CIMC)
Processor	Intel Xeon Scalable Processors
Memory	Up to 3TB DDR4
Drive Bays	Up to 12 x 3.5-inch drives