Independent mode

In independent memory mode, memory channels can be populated with DIMMs in any order and you can populate all channels for each processor in any order with no matching requirements. Independent memory mode provides the highest level of memory performance, but lacks failover protection. The DIMM installation order for independent memory mode varies based on the number of processors and memory modules installed in the server.

Follow the rules below when installing memory modules in independent mode:

All memory modules to be installed must be of the same type.
Memory modules from different vendors are supported.
There must be at least one DDR4 DIMM per socket.
In each memory channel, populate slot 0 first.
If a memory channel has two DIMMs, populate the DIMM with a higher number of ranks in slot 0; if the two DIMMs have the same number of ranks, populate the DIMM with a higher capacity in slot 0.
A maximum of 8 logical ranks (ranks seen by the host) per channel is allowed.
A maximum of two different DIMM capacities are supported per system.
- For channels A, C, E, and G, populated DIMMs must have the same total capacity for each channel.
- For channels B, D, F, and H, populated DIMMs must have the same total capacity for each channel, which can be different from that of the other set (channels A, C, E, and G).
If there are more than two DIMMs, populate them in a right-and-left symmetrical manner across a CPU socket.

The following table shows the sequence of populating memory modules (with the same capacity) for independent mode when only one processor (CPU 1) is installed.

Table 1. Independent mode with one processor (DIMMs with the same capacity)
Configuration	DIMM slots
	DIMM slots
	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16
1 DIMM			3
2 DIMMs			3				7
4 DIMMs¹			3				7			10				14
6 DIMMs	1		3				7			10				14		16
8 DIMMs^1,2	1		3		5		7			10		12		14		16
12 DIMMs	1	2	3	4			7	8	9	10			13	14	15	16
16 DIMMs^1,2	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16

Note

DIMM configurations that support Sub NUMA Clustering (SNC), which can be enabled via UEFI. SNC is not supported if DIMM population does not follow the sequence indicated by the table above.
DIMM configurations that support Software Guard Extensions (SGX). See Enable Software Guard Extensions (SGX) to enable this feature.

The following table shows the sequence of populating memory modules (with different capacities) for independent mode when only one processor (CPU 1) is installed.

Table 2. Independent mode with one processor (DIMMs with different capacities)
Configuration	DIMM slots
	DIMM slots
	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16
2 DIMMs			3		5
4 DIMMs			3		5							12		14
8 DIMMs^1,2	1		3		5		7			10		12		14		16
12 DIMMs^1,2	1		3	4	5		7	8	9	10		12	13	14		16
16 DIMMs^1,2	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16

Note

DIMM configurations that support Sub NUMA Clustering (SNC), which can be enabled via UEFI. SNC is not supported if DIMM population does not follow the sequence indicated by the table above.
DIMM configurations that support Software Guard Extensions (SGX). See Enable Software Guard Extensions (SGX) to enable this feature.

The following table shows the sequence of populating memory modules (with the same capacity) for independent mode when two processors (CPU 1 and CPU 2) are installed.

Table 3. Independent mode with two processors (DIMMs with the same capacity)
Configuration	DIMM slots
Configuration	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16
2 DIMMs			3
4 DIMMs			3				7
8 DIMMs¹			3				7			10				14
12 DIMMs	1		3				7			10				14		16
16 DIMMs^1,2	1		3		5		7			10		12		14		16
24 DIMMs	1	2	3	4			7	8	9	10			13	14	15	16
32 DIMMs^1,2	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16
Configuration	DIMM slots
Configuration	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31	32
2 DIMMs			19
4 DIMMs			19				23
8 DIMMs¹			19				23			26				30
12 DIMMs	17		19				23			26				30		32
16 DIMMs^1,2	17		19		21		23			26		28		30		32
24 DIMMs	17	18	19	20			23	24	25	26			29	30	31	32
32 DIMMs^1,2	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31	32

Note

DIMM configurations that support Sub NUMA Clustering (SNC), which can be enabled via UEFI. SNC is not supported if DIMM population does not follow the sequence indicated by the table above.
DIMM configurations that support Software Guard Extensions (SGX). See Enable Software Guard Extensions (SGX) to enable this feature.

The following table shows the sequence of populating memory modules (with different capacities) for independent mode when two processors (CPU 1 and CPU 2) are installed.

Table 4. Independent mode with two processors (DIMMs with different capacities)
Configuration	DIMM slots
Configuration	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16
4 DIMMs			3		5
8 DIMMs			3		5							12		14
16 DIMMs^1,2	1		3		5		7			10		12		14		16
24 DIMMs^1,2	1		3	4	5		7	8	9	10		12	13	14		16
32 DIMMs^1,2	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16
Configuration	DIMM slots
Configuration	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31	32
4 DIMMs			19		21
8 DIMMs			19		21							28		30
16 DIMMs^1,2	17		19		21		23			26		28		30		32
24 DIMMs^1,2	17		19	20	21		23	24	25	26		28	29	30		32
32 DIMMs^1,2	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31	32

Note

DIMM configurations that support Sub NUMA Clustering (SNC), which can be enabled via UEFI. SNC is not supported if DIMM population does not follow the sequence indicated by the table above.
DIMM configurations that support Software Guard Extensions (SGX). See Enable Software Guard Extensions (SGX) to enable this feature.

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