NEC N8100-1575F, User Manual

Page: 331 / 378

Upgrading Your Server 11-17
Using the Memory RAS Features
The server has RAS feature including "Standard memory configuration (x4 SDDC ECC memory)
and "LockStep (x8 SDDC ECC memory) feature. SDDC (Single Device Correction) allows
automatic correction of memory error (multi-bit error).
IMPORTANT:
„
To use x4 SDDC ECC memory feature, additional 2-GB/4-GB
memory board is required. The factory-installed two 1-GB DIMMs
and additional 1-GB memory board is unavailable for x4 SDDC
feature.
„
"LockStep (x8 SDDC ECC memory) feature cannot be used
together with "Standard memory configuration (x4 SDDC ECC
memory)
The memory area on the motherboard of the server is divided into two memory channels as shown
in the figure below.
The LockStep feature keeps memory redundancy between memory channels by monitoring or
altering memory active/inactive status, respectively.
CPU1
Memory controller
CH0 CH1
CPU1_DIMM 3 CPU1_DIMM 4
CPU1_DIMM 1 CPU1_DIMM 2
CPU2
Memory controller
CH0 CH1
CPU2_DIMM 3 CPU2_DIMM 4
CPU2_DIMM 1 CPU2_DIMM 2