Available Memory Configurations - Intel SR4850HW4 - Server Platform - 0 MB RAM Product Manual

Platform Description

Available Memory Configurations

Four memory configurations are available in the BIOS Setup utility.
Maximum Performance: Maximum Performance is the default configuration in BIOS setup.
With this configuration, the BIOS first attempts to configure the memory boards as four-way
interleaved. If four-way interleaving cannot be accomplished, it will attempt to two-way
interleave. It will then use one-way interleaving if any remaining memory cannot be four-way
or two-way interleaved. This interleaving process configures the memory for maximum
performance. This configuration cannot be used if you want hot-add or hot-replace memory.
Maximum Compatibility: Maximum Compatibility provides the most flexibility with DIMMs
and memory boards. This option allows memory to be hot-added. Server performance will be
reduced due to one-way interleaving.
Memory Mirroring: The Memory Mirroring feature provides redundancy. It uses either two or
four memory boards, paired as sets of two. Memory boards in slots A and B form one set.
Memory boards in slots C and D form the second set. One board within a set of memory boards
duplicates the second board in the set. Each memory board in a set must have the same amount
of memory installed.
When a hardware or DIMM error is detected on a primary memory board, the second board
becomes the primary board and remains primary until the failing board or DIMM is replaced.
Memory Mirroring uses board-level redundancy, allowing for hot-replacement. Hot-add is
supported by adding two additional mirrored memory boards.
The BIOS turns on the mirror LED on each memory board when the system is configured for
mirroring.
Memory RAID: If the server contains four memory boards with equal memory capacity, the
system can be configured for Memory RAID. Data is written to three of the memory boards
while one is reserved for redundant parity information. This reduces the total overall available
memory by one-fourth. The RAID LED on the memory board will indicate that the memory
board is in a RAID configuration.
When a DIMM rank or board fails, the system will continue to operate with the remaining three
boards by recreating the data from the failed board. The system loses its redundancy at this
point, and will remain in this non-redundant state until the failing board and/or memory can
then be replaced.
This configuration allows for hot-replacement of failing memory boards and hot-add and hot-
replacement of memory DIMMs.
38 Intel® Server Platforms SR4850HW4 & SR4850HW4/M Product Guide