Acer Network Device Altos R520 - Manual (Page 82)

3 System upgrade 72
To upgrade to a four FBDIMM mirrored memory configuration, four
additional FBDIMMs must be added to the system. All four memory
modules in the second set must be identical to the first with the
exception of speed. The memory controller hub (MCH) will adjust to
the low-speed FBDIMM memory.
Note: After upgrading system memory to this feature, the
memory RAS setting in the BIOS setup must be set to Mirroring
configuration. Refer to the BIOS setup’s Configure Memory RAS
and Performance screen on page 101 for more information.
Memory sparing configuration
The system provides FBDIMM sparing capabilities. Sparing is a RAS
feature that involves configuring a FBDIMM to be placed in reserve so
it can be use to replace a failed FBDIMM.
Note: FBDIMM sparing occurs within a given bank of memory and
is not supported across branches.
The system supports two types of memory sparing configurations:
• Single branch mode sparing
In single branch mode sparing the following population rules must
be observed:
• DIMM slots A1 and B1 or DIMM slots A2 and B2 must be
identical in organization, speed, and speed
• DIMM slots A1 and A2 or DIMM slots B1 and B2 need not be
identical in organization, size and speed
• Sparing should be enabled in the BIOS setup utility
• System BIOS will configure rank sparing mode.
• The largest memory size among the DIMM pairs (DIMM_A1,
DIMM_B1) and (DIMM_A2, DIMM_B2) will be selected as the
spare pair unit.
• Dual branch mode sparing
Dual branch mode sparing requires that all eight FBDIMM slots be
populated and must comply with the following population rules: