User`s guide

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5: Advanced Serverboard Setup
Mismatching Processor and DIMM Speeds
The processor is rated for the maximum DIMM speed that it will support. Configuring memory
DIMMs that have a DIMM speed that is greater than the processor capability will result in the
memory DIMM running at the maximum speed of the processor—not the maximum speed of the
DIMM.
Three conditions must be met to have a memory speed of 1333 MT/s:
• The processor must be capable of supporting (1333 MT/s) / 2.
• The DIMM must be capable of running at 1333 MT/s.
• For Nehalem processors, only one DIMM is placed on each channel. Westmere processors
can support two DIMMs on each channel.
Placing three DIMMs on the channel will cause the DIMMs to run at 800 MT/s for both Nehalem
and Westmere processors.