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3 System upgrade

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:

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Acer Altos R520 manual Memory sparing configuration