Installing System Components 61
System Memory
Your system supports DDR3 registered DIMMs (RDIMMs). Single and
dual-rank DIMMs can be 1067 or 1333 MHz, and quad-rank DIMMs can
be 1067 MHz.
The system contains 18 memory sockets split into two sets of nine sockets,
one set for each processor. Each nine-socket set is organized into three
channels of three memory sockets per channel.
The maximum memory that is supported on your system varies according to
the types and sizes of memory modules being used:
• Single-rank, dual-rank, and quad-rank RDIMMs of sizes 1 GB, 2 GB,
4GB, and 8 GB are supported for a total of up to 144 GB.
• Quad-rank RDIMMs (two per channel) are supported for a total of
upto 96 GB.

General Memory Module InstallationGuidelines

To ensure optimal performance of your system, observe the following general
guidelines when configuring your system memory.
NOTE: Memory configurations that fail to observe these guidelines can prevent
your system from starting and producing any video output.
• Except for memory channels that are unused, all populated memory
channels must have identical configurations.
• The memory configuration for each processor must be identical.
• Memory modules of different sizes can be mixed in A1–A4 or B1–B4
(forexample, 2 GB and 4 GB), but all populated channels must have
identical configurations.
• For optimizer mode, memory modules are installed in the numeric order of
the sockets beginning with A1 or B1.
• For memory mirroring or advanced ECC mode, the two channels furthest
from the processor are unused and memory modules are installed
beginning with channel A1 or B1 and proceeding with channel A2 or B2.
• Advanced ECC mode requires memory modules that use x4 or x8 DRAM
device widths.
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