Memory module installation rules

Memory modules must be installed in a specific order based on the memory configuration that you implement on your server.

Your server has 16 memory slots and supports:

Minimum: 8 GB
Maximum: 2 TB
Type (depending on the model):
- TruDDR4 2933, single-rank or dual-rank, 8 GB/16 GB/32 GB/64 GB RDIMM
- TruDDR4 3200, dual-rank, 16 GB/32 GB/64 GB RDIMM
- TruDDR4 2933, quad-rank, 128 GB 3DS RDIMM
- TruDDR4 3200, quad-rank, 128 GB 3DS RDIMM (Only 7003 series processors are supported.)

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

Follow below rules when you install or replace a memory module:

Memory modules in your server must be the same type.
Memory modules from different vendors are supported.
Memory modules with different capacities are supported. Install the memory module that has the higher capacity first.
Memory modules with different ranks are supported. Install the memory module with the highest rank first.
Do not mix x4 and x8 DIMMs in the same channel.
DIMMs of 3200 MHz and 2933 MHz are supported:
- 2933 MHz DIMMs: operate at 2933 MHz for both 1 DIMM per channel and 2 DIMMs per channel.
- 3200 MHz DIMMs: operate at 3200 MHz when 1 DIMM per channel, but operate at 2933 MHz when 2 DIMMs per channel.
- Mixing of 2933 MHz and 3200 MHz DIMMs is supported in different channels, operating at 2933 MHz.
Note
Operating speed depends on the processor model. For example, if the processor only supports a memory bus speed of 2666 MHz, all the installed DIMMs operate at 2666 MHz.
Install a memory module filler if there is no memory module installed in the slot.
For 12x3.5 HDD and middle HDD configurations, 128GB DIMM is not supported.

The following illustration helps you to locate the memory slots on the system board.

Figure 1. DIMM locations
DIMM locations on the system board

The following table shows the relationship between the processors, memory controllers, memory channels, slots, and DIMM numbers. The system has eight channels, and supports up to two DIMMs per channel. DIMMs must be populated from farthest slot (slot 1) to closest slot (slot 0) to the processor on a per-channel basis when a data bus daisy chain topology is used. DIMMs may be populated in either slot on a per-channel basis when a data bus balanced tee route topology is used.

Table 1. DIMM installation order
Unified Memory Controller (UMC)	UMC2		UMC3		UMC1		UMC0		UMC6		UMC7		UMC5		UMC4
Channel (CH)	D		C		B		A		E		F		G		H
CH slot	1	0	1	0	1	0	1	0	0	1	0	1	0	1	0	1
DIMM number	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16
1 DIMM			3
2 DIMMs	1		3
3 DIMMs	1		3											14
4 DIMMs	1		3											14		16
5 DIMMs	1		3				7							14		16
6 DIMMs	1		3		5		7							14		16
7 DIMMs	1		3		5		7			10				14		16
8 DIMMs	1		3		5		7			10		12		14		16
9 DIMMs	1		3	4	5		7			10		12		14		16
10 DIMMs	1	2	3	4	5		7			10		12		14		16
11 DIMMs	1	2	3	4	5		7			10		12	13	14		16
12 DIMMs	1	2	3	4	5		7			10		12	13	14	15	16
13 DIMMs	1	2	3	4	5		7	8		10		12	13	14	15	16
14 DIMMs	1	2	3	4	5	6	7	8		10		12	13	14	15	16
15 DIMMs	1	2	3	4	5	6	7	8	9	10		12	13	14	15	16
16 DIMMs	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16

Note

There are performance-optimized 6-DIMM and 12-DIMM configurations for server models with 7003 series CPU. For details, see the table below.

DIMM Qty	DIMM population order
6	1, 3, 7, 10, 14, 16
12	1, 2, 3, 4, 7, 8, 9, 10, 13, 14, 15, 16

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