Asus DSBF-DM/SAS - Manual (Page 40)

2-20 Chapter 2: Hardware information
• Each branch contains its own sparing engine and can be enabled or
disabled separately.
• This motherboard does not support rank sparing across branches.
• This motherboard does not support rank sparing when in mirror mode.
• The DIMM rank with the largest size will be assigned as spare rank.
Data can only be copied from a smaller sized rank to a larger sized
one.
• A DIMM can contain only one or two ranks. To support sparing
function, a DIMM channel should contain at least two ranks.
• When sparing function is enabled, the usable memory size will reduce
the size of the spare ranks.
Memory Sparing
At configuration time, a DIMM rank is set aside to replace a defective DIMM rank.
When the error rate for a failing DIMM rank reaches a pre-determined threshold,
the memory sparing function will issue an interrupt and initiate a spare copy. At the
completion of the copy, the failing DIMM rank is disabled and the “spared” DIMM
rank will be used in its place. Refer to section 4.4.2 Chipset Configuration and
configure the options of Branch 0 Rank Sparing or Branch 1 Rank Sparing to
enable the memory sparing functions. The default BIOS setting is disabled.
The following tables show memory configurations with Memory Sparing function in
Branch 0.
One DIMM per channel (two ranks)
Branch0
Channel 0 Channel 1
DIMM_00 (onboard)
(1024MB*2 Ranks)
DIMM_10 (onboard)
(1024MB*2 Ranks)
Rank 0
(512 MB)
Rank 1
(512 MB)
Rank 0
(512 MB)
Rank 1
(512 MB)
Sparing
Memory space 512 MB 512 MB
Total Memory 1024 MB