Intel Server Board S5000PAL - Manual (Page 30)

Intel
®
Server Board S5000PAL / S5000XAL TPS Functional Architecture
Revision 1.4
Intel order number: D31979-007
31
3.1.3.4 Non-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.
TP02301
DIMM D2
DIMM D1
DIMM C2
DIMM C1
DIMM B2
DIMM B1
DIMM A2
DIMM A1
Branch 0
MCH
Channel A
Channel B
Channel D
Channel C
Branch 1
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.
3.1.3.4.1 Mirrored 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.