NEC N8100-2089F User Manual page 76

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.

Refer to Chapter 2 (1. System BIOS Setup) in "Maintenance Guide", change parameters as shown below,
save the settings and exit from SETUP.
[Advanced] – [Memory Configuration] – [Memory RAS Mode] : Change to [Lock Step]

After restart, run SETUP again, and check if Lock Step is displayed for the following parameter.
Advanced  Memory Configuration  Memory Information  CPUx_DIMMx Status

Installation order depends on CPU configuration. See the figure below.
2-CPU
REAR
configuration
(Empty)
(Empty)
1st set
3rd set
1st set
3rd set
4th set
2nd set
4th set
2nd set
(Empty)
(Empty)
Memory Lock Step cannot be configured in the following cases:

Memory Lock Step between memory channels of different memory controllers (CPU)

Memory Lock Step within the same memory channel
Notes on Configuring Lock Step
When you additionally install or remove DIMMs that unable to configure Memory LockStep configuration,
Memory RAS Mode is changed to "Independent".
"LockStep" is removed from Advanced  Memory Configuration  Memory Information  CPUx_DIMMx
Status xxxx MB (LockStep) in BIOS SETUP.
76
Express5800/T120e User's Guide
1. Installing Internal Optional Devices
1-CPU
FRONT
configuration
(Empty)
(Empty)
1st set
2nd set
1st set
2nd set