Populating DIMMs considerations, Order and Ranks

The Nehalem and Westmere platforms offer a wide variety of DIMM configurations. Some of the various DIMM configurations are shown below

Feature	Values
Number of DIMMs	1,2 or 3
Number of DIMMs slots per channel	2 or 3 DIMM Slots
Number of DIMMs populated per channel	1,2 or 3 DIMM per channel
DIMM Frequencies	DDR3-800, DDR3-1066, DDR3-1300

 Table 1:  DIMM Configurations

Populating DIMMs within a channel

When populating DIMMs in a three slots per channel configurations, a “fill-farthest” approach is used, meaning, the farthest DIMM from the processor is used first. If a Quad-rank DIMM is used, it should be populated first.

Figure 1:  DIMM Population within a channel

DIMM population in an 18 DIMM slots configuration

	CPU1		CPU2
	Slot Number	Population Order	Slot Number	Population Order
Channel1	1	G	1	G
	2	D	2	D
	3	A	3	A
Channel2	4	H	4	H
	5	E	5	E
	6	B	6	B
Channel3	7	I	7	I
	8	F	8	F
	9	C	9	C

 Table 2:  DIMM Population in 18 DIMM Slots

Additional population requirements

1. All DIMMS must be DDR3 DIMMs.
2. The 5600 series support low voltage DDR3 memory (DDR3L) 1.35V, the 5500 supports only 1.5V, if mixed they will work at 1.5V.
3. Mixing Registered and Unbuffered DIMMs is not allowed.
4. The maximum supported speed is defined by the BIOS and not the DIMMs
5. Mixing different timing DIMMs will force the operation at the slowest DIMM for both processors.

RDIMM Ranks population in a three slots per channel configuration

Configuration Number	Max Speed	DIMM2	DIMM1	DIMM0
1	DDR3-1333	-	-	Single-rank
2	DDR3-1333	-	-	Dual-rank
3	DDR3-1066	-	-	Quad-rank
4	DDR3-1066	-	Single-rank	Single-rank
5	DDR3-1066	-	Single-rank	Dual-rank
6	DDR3-1066	-	Dual-rank	Single-rank
7	DDR3-1066	-	Dual-rank	Dual-rank
8	DDR3-800	-	Single-rank	Quad-rank
9	DDR3-800	-	Dual-rank	Quad-rank
10	DDR3-800	-	Quad-rank	Quad-rank
11	DDR3-800	Single-rank	Single-rank	Single-rank
12	DDR3-800	Single-rank	Single-rank	Dual-rank
13	DDR3-800	Single-rank	Dual-rank	Single-rank
14	DDR3-800	Dual-rank	Single-rank	Single-rank
15	DDR3-800	Single-rank	Dual-rank	Dual-rank
16	DDR3-800	Dual-rank	Single-rank	Dual-rank
17	DDR3-800	Dual-rank	Dual-rank	Single-rank
18	DDR3-800	Dual-rank	Dual-rank	Dual-rank

 Table 3:  DIMM RANKS Population in 3 slots per channel

This concludes all the basic elements we need for configuring the perfect server.

-Partykof