⚫ 
a: The maximum number of DDR4 memory modules is based on dual-processor 
configuration. The value is halved for a server with only one processor. 
⚫ 
b: DPC (DIMM per channel) indicates the number of memory modules per channel. 
⚫ 
The information listed in this table is for reference only. For details, consult the local 
sales representative. 
 
5.1.4.1.4 DIMM Installation Rules 
 
This section applies to a server fully configured with DDR4 memory modules. If PMem modules are 
used together, see 5.1.4.2.4 DIMM Installation Rules. 
Observe the following when configuring DDR4 memory modules: 
⚫ 
Install memory modules only when corresponding processors are installed. 
⚫ 
Do not install LRDIMMs and RDIMMs in the same server. 
⚫ 
Install filler memory modules in vacant slots. 
Observe the following when configuring DDR4 memory modules in specific operating mode: 
⚫ 
Rank sparing mode 
−  Comply with the general installation guidelines. 
−  At least two ranks must be configured for each channel. 
−  A maximum of two standby ranks can be configured for each channel. 
−  The capacity of a standby rank must be greater than or equal to that of other ranks 
in the same channel. 
⚫ 
Memory mirroring mode 
−  Comply with the general installation guidelines.