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Independent memory 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.

Attention

Independent memory mode guidelines:

There should be at least one memory module per processor.
If only one DIMM is populated in a channel, populate it in the slot furthest away from CPU of that channel.
Always populate DIMMs with a higher electrical loading in slot 0 followed by slot 1.
- When single or dual rank RDIMMs are populated for 2DPC, always populate the higher quantity rank DIMM first in the farthest DIMM slot, followed by the nearest DIMM slot.
- If two DIMMs on a channel have identical ranks, then populate the one with the higher capacity on slot 0.
System operating speed depends on the processor model, DIMM per channel, operating mode, and stretch goal support on each system.
A maximum of 8 logical ranks (ranks seen by the host) per channel is allowed.
A maximum of two different types (capacity) is supported per system.
Channel A, C, E, G (DIMM slot 14, 13, 10, 9, 3, 4, 7, and 8) must be populated with the same total capacity per channel if populated.
Channel B, D, F, H (DIMM slot 16, 15, 12, 11, 1, 2, 5, and 6) must be populated with the same total capacity per channel if populated, but can be populated different from channel A, C, E, G (DIMM slot 14, 13, 10, 9, 3, 4, 7, and 8).
Memory population must be identical on all CPUs.

Note

When adding one or more DIMMs during a memory upgrade, you might need to remove some DIMMs that are already installed to new locations.

Independent memory mode with one processor and same capacity memory modules

Table 1. Independent memory mode with one processor and same capacity memory modules
Total DIMMs	Processor 1																	Total DIMMs
Total DIMMs	1	2	3	4	5	6	7	8		9	10	11	12	13	14	15	16	Total DIMMs
1															14			1
2											10				14			2
4¹			3				7				10				14			4¹
6	1		3				7				10				14		16	6
8^1,2	1		3		5		7				10		12		14		16	8^1,2
12	1	2	3	4			7	8		9	10			13	14	15	16	12
16^1,2	1	2	3	4	5	6	7	8		9	10	11	12	13	14	15	16	16^1,2

Note

DIMM configurations that support Sub NUMA Clustering (SNC), which can be enabled via UEFI.
DIMM configurations that support Software Guard Extensions (SGX), see Enable Software Guard Extensions (SGX) to enable this feature.

Independent memory mode with one processor and different capacity memory modules

Table 2. Independent memory mode with one processor and different capacity memory modules
Total DIMMs	Processor 1																	Total DIMMs
Total DIMMs	1	2	3	4	5	6	7	8		9	10	11	12	13	14	15	16	Total DIMMs
2													12		14			2
4			3		5								12		14			4
8^1,2	1		3		5		7				10		12		14		16	8^1,2
12^1,2	1		3	4	5		7	8		9	10		12	13	14		16	12^1,2
16^1,2	1	2	3	4	5	6	7	8		9	10	11	12	13	14	15	16	16^1,2

Note

DIMM configurations that support Sub NUMA Clustering (SNC), which can be enabled via UEFI.
DIMM configurations that support Software Guard Extensions (SGX), see Enable Software Guard Extensions (SGX) to enable this feature.

Independent memory mode with two processors and same capacity memory modules

Table 3. Independent mode with two processors and same capacity memory modules (processor 1)
Total DIMMs	Processor 1																	Total DIMMs
Total DIMMs	1	2	3	4	5	6	7	8		9	10	11	12	13	14	15	16	Total DIMMs
2															14			2
4											10				14			4
8¹			3				7				10				14			8¹
12	1		3				7				10				14		16	12
16^1,2	1		3		5		7				10		12		14		16	16^1,2
24	1	2	3	4			7	8		9	10			13	14	15	16	24
32^1,2	1	2	3	4	5	6	7	8		9	10	11	12	13	14	15	16	32^1,2

Table 4. Independent mode with two processors and same capacity memory modules (processor 2)
Total DIMMs	Processor 2																	Total DIMMs
Total DIMMs	17	18	19	20	21	22	23	24		25	26	27	28	29	30	31	32	Total DIMMs
2			19															2
4			19				23											4
8¹			19				23				26				30			8¹
12	17		19				23				26				30		32	12
16^1,2	17		19		21		23				26		28		30		32	16^1,2
24	17	18	19	20			23	24		25	26			29	30	31	32	24
32^1,2	17	18	19	20	21	22	23	24		25	26	27	28	29	30	31	32	32^1,2

Note

DIMM configurations that support Sub NUMA Clustering (SNC), which can be enabled via UEFI.
DIMM configurations that support Software Guard Extensions (SGX), see Enable Software Guard Extensions (SGX) to enable this feature.

Independent memory mode with two processors and different capacity memory modules

Table 5. Independent mode with two processors and different capacity memory modules (processor 1)
Total DIMMs	Processor 1																	Total DIMMs
Total DIMMs	1	2	3	4	5	6	7	8		9	10	11	12	13	14	15	16	Total DIMMs
4													12		14			4
8			3		5								12		14			8
16^1,2	1		3		5		7				10		12		14		16	16^1,2
24^1,2	1		3	4	5		7	8		9	10		12	13	14		16	24^1,2
32^1,2	1	2	3	4	5	6	7	8		9	10	11	12	13	14	15	16	32^1,2

Table 6. Independent mode with two processors and different capacity memory modules (processor 2)
Total DIMMs	Processor 2																	Total DIMMs
Total DIMMs	17	18	19	20	21	22	23	24		25	26	27	28	29	30	31	32	Total DIMMs
4			19		21													4
8			19		21								28		30			8
16^1,2	17		19		21		23				26		28		30		32	16^1,2
24^1,2	17		19	20	21		23	24		25	26		28	29	30		32	24^1,2
32^1,2	17	18	19	20	21	22	23	24		25	26	27	28	29	30	31	32	32^1,2

Note

DIMM configurations that support Sub NUMA Clustering (SNC), which can be enabled via UEFI.
DIMM configurations that support Software Guard Extensions (SGX), see Enable Software Guard Extensions (SGX) to enable this feature.

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Independent memory mode with one processor and same capacity memory modules
Independent memory mode with one processor and different capacity memory modules
Independent memory mode with two processors and same capacity memory modules
Independent memory mode with two processors and different capacity memory modules