NEC Express5800/R120b-1 User Manual page 392

9-36 Upgrading Your Server
Memory LockStep feature (x8 SDDC)
In LockStep feature, the DIMMs in two groups corresponding to two memory channels (channels 0
and 1) is multiplexed and operated in parallel to enable x8 SDDC (x8 Single Device Data
Correction). With this feature, a single device can detect and correct one to eight-bit error.
IMPORTANT:
The LockStep feature uses channels 0 and 1. In LockStep configuration, the
memory channel 2 of each CPU (CPU1-DIMM3/6, CPU2-DIMM3/6) is disabled.
To use the LockStep feature, an additional memory stick
(N8102-387/388/389/390/391) is required.
CPU1-DIMM 4
CPU1-DIMM 1
CPU2-DIMM 4
CPU2-DIMM 1
Memory controller
CH0
CPU1-DIMM 5
CPU1-DIMM 2
Memory controller
CH0
CPU2-DIMM 5
CPU2-DIMM 2
CPU1
CH1
CPU1-DIMM 6
CPU1-DIMM 3
CPU2
CH1
CPU2-DIMM 6
CPU2-DIMM 3
CH2
CH2