NEC Express5800 Series User Manual page 70

Chapter 2 Preparations
Memory Lock Step feature can be used under the following conditions:

Install two DIMMs that operate in parallel in memory socket.

All the installed DIMMs should have the same model number.

See Chapter 2 (1. System BIOS) in "Maintenance Guide" to change parameters as shown below.
Advanced  Memory Configuration  Memory RAS Mode : Change to Lock Step.

After restarting, run SETUP again, and check if Lock Step is displayed for the following parameter.
Advanced  Memory Configuration  Memory Information  CPUx_DIMMx Status

The Memory Lock Step feature cannot be used together with the Memory Mirroring feature.

Installation order depends on CPU configuration. See the figure below.
2-CPU
configuration
4th set
8th set
4th set
8th set
1st set
5th set
1st set
5th set
6th set
2nd set
6th set
2nd set
7th set
3rd set
7th set
3rd set
CPU1_DIMM1
CPU1_DIMM2
CPU1_DIMM3
CPU1_DIMM4
CPU1_DIMM5
CPU1_DIMM6
CPU1_DIMM7
CPU1_DIMM8
CPU2_DIMM1
CPU2_DIMM2
CPU2_DIMM3
CPU2_DIMM4
CPU2_DIMM5
CPU2_DIMM6
CPU2_DIMM7
CPU2_DIMM8
70
DIMM installation order
Slot
1-CPU configuration
1
1
2
2
3
3
4
4








Express5800/T120g User's Guide
1. Installing Internal Optional Devices
1-CPU
configuration
1st set
3rd set
1st set
3rd set
4th set
2nd set
4th set
2nd set
2-CPU configuration
1
1
3
3
5
5
7
7
2
2
4
4
6
6
8
8