Memory module installation rules and order

Supported memory types

For information on the types of memory module supported by this server, see Memory section in Technical Specifications.

For a list of supported memory options, see Lenovo ServerProven website.

Information about optimizing memory performance and configuring memory is available at the Lenovo Press website:

Memory - Lenovo Press

In addition, you can take advantage of a memory configurator, which is available at the following site:

Lenovo Enterprise Solutions Configurator (Memory Configurations)

Specific information about the required installation order of memory modules in your server based on the system configuration and memory mode that you are implementing is shown below.

• Memory modules and processors layout of servers without Compute Complex Neptune Core Module

• Memory modules and processors layout of servers with Compute Complex Neptune Core Module

Memory modules and processors layout of servers without Compute Complex Neptune Core Module​

The following illustration helps you to locate the memory module slots on the processor board for servers without Compute Complex Neptune Core Module. The memory-channel identification table below shows the relationship between the processors, memory controllers, memory channels, and memory module slot numbers.

Figure 1. Memory module slots on the processor board for servers without Compute Complex Neptune Core Module

Table 1. Memory slot and channel identification for servers without Compute Complex Neptune Core Module

Processor	CPU 1
Controller	iMC7		iMC6		iMC5		iMC4		iMC0		iMC1		iMC2		iMC3
Channel	CH7		CH6		CH5		CH4		CH0		CH1		CH2		CH3
Slot No.	0	1	0	1	0	1	0	1	1	0	1	0	1	0	1	0
DIMM No.	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1
Processor	CPU 2
Controller	iMC7		iMC6		iMC5		iMC4		iMC0		iMC1		iMC2		iMC3
Channel	CH7		CH6		CH5		CH4		CH0		CH1		CH2		CH3
Slot No.	0	1	0	1	0	1	0	1	1	0	1	0	1	0	1	0
DIMM No.	32	31	30	29	28	27	26	25	24	23	22	21	20	19	18	17

• Slot No.: DIMM slot number in each memory channel. Each memory channel has two DIMM slots: slot 0 (further from the processor) and slot 1 (closer to the processor).

• DIMM No.: DIMM slot number on the processor board. Each processor has 16 DIMM slots.

Memory modules and processors layout of servers with Compute Complex Neptune Core Module​

The following illustration helps you to locate the memory module slots on the processor board for of servers with Compute Complex Neptune Core Module. The memory-channel identification table below shows the relationship between the processors, memory controllers, memory channels, and memory module slot numbers.

Figure 2. Memory module slots on the processor board for servers with Compute Complex Neptune Core Module

Table 2. Memory slot and channel identification for servers with Compute Complex Neptune Core Module

Processor	CPU 1
Controller	iMC7	iMC6	iMC5	iMC4	iMC0	iMC1	iMC2	iMC3
Channel	CH7	CH6	CH5	CH4	CH0	CH1	CH2	CH3
Slot No.	0	0	0	0	0	0	0	0
DIMM No.	16	14	12	10	7	5	3	1
Processor	CPU 2
Controller	iMC7	iMC6	iMC5	iMC4	iMC0	iMC1	iMC2	iMC3
Channel	CH7	CH6	CH5	CH4	CH0	CH1	CH2	CH3
Slot No.	0	0	0	0	0	0	0	0
DIMM No.	32	30	28	26	23	21	19	17

• Slot No.: DIMM slot number in each memory channel. Each memory channel has one DIMM slot.

• DIMM No.: DIMM slot number on the processor board. Each processor has eight DIMM slots.

Memory module installation guideline​

• At least one DIMM is required for each processor. Install at least eight DIMMs per processor for good performance.

• When you replace a DIMM, the server provides automatic DIMM enablement capability without requiring you to use the Setup Utility to enable the new DIMM manually.

• For memory module installation rules and orders, see:

  • DDR5 DIMMs only

  • DDR5 RDIMMs mixed with CXL memory modules