User`s guide
Upgrading Your Server 9-31
Using the Memory RAS Features
The server has a RAS feature including "Standard memory configuration (x4 SDDC ECC memory), "Memory mirroring
feature", and "LockStep (x8 SDDC ECC memory) feature. SDDC (Single Device Correction) allows automatic correction of
memory error (multi-bit error).
IMPORTANT:
The memory mirroring and LockStep features are not available in the normal memory
configuration. Contact your service representative for details.
To use x4 SDDC ECC memory feature, an additional 2-GB/4-GB/8-GB memory board is
required. The factory-installed two 1-GB DIMMs and an additional 1-GB memory board is
unavailable for x4 SDDC feature.
"Memory mirroring feature" and "LockStep (x8 SDDC ECC memory) feature cannot be used
in the normal memory configuration.
The memory area on the motherboard of the server is divided into two memory channels as shown in the figure below.
Memory controller Memory controller
The memory mirroring and LockStep features keep memory redundancy between memory channels by monitoring or altering
memory active/inactive status, respectively.