Intel S5000XAL manual Non-mirrored mode memory upgrades, Recommended Four Dimm Configuration

Intel® Server Board S5000PAL / S5000XAL TPS Functional Architecture

3.1.3.4Non-mirrored mode memory upgrades

The minimum memory upgrade increment is two DIMMs per branch. The DIMMs must cover the same slot position on both channels. DIMMs pairs must be identical with respect to size, speed, and organization. DIMMs that cover adjacent slot positions do not need to be identical.

When adding two DIMMs to the configuration shown in Figure 12, the DIMMs should be populated in DIMM slots C1 and D1 as shown in the following diagram. Populated DIMM slots are shown in Grey.

MCH

Branch 0

Channel B

Channel A

A1
DIMM	A2
DIMM B1
DIMM		B2
	DIMM C1
	DIMM C2
		DIMM D1
		DIMM	D2
		DIMM

Channel C Channel D

Branch 1

TP02301

Figure 13. Recommended Four DIMM Configuration

Functionally, DIMM slots A2 and B2 could also have been populated instead of DIMM slots C1 and D1. However, your system will not achieve equivalent performance. Figure 13 shows the supported DIMM configuration that is recommended because it allows both memory branches from the MCH to operate independently and simultaneously. FBD bandwidth is doubled when both branches operate in parallel.

3.1.3.4.1Mirrored Mode Memory Configuration

When operating in mirrored mode, both branches operate in lock step. In mirrored mode, branch 1 contains a replicate copy of the data in branch 0. The minimum DIMM configuration to support memory mirroring is four DIMMs, populated as shown in Figure 13 above. All four DIMMs must be identical with respect to size, speed, and organization.

To upgrade a four DIMM mirrored memory configuration, four additional DIMMs must be added to the system. All four DIMMs in the second set must be identical to the first with the exception of speed. The MCH will adjust to the lowest speed DIMM.

Revision 1.4	31
	Intel order number: D31979-007