Fujitsu PRIMERGY RX2520 M5, Upgrade And Maintenance Manual, Page: 261 / 508

Independent Channel mode with different DIMMs
– Same letter represents identical DIMMs (capacity, rank).
– If using two different DIMMs, use a "near-balanced" platform configuration:
– all available memory channels and sockets populated equally
– identical DIMMs in each "row", but different sized DIMMs in row #1 and
row #2
– Marked (*) quantity of DIMMs are not recommended because of unbalanced
configurations.
– Unbalanced configurations can lead to significantly reduced bandwidth
because the system will fracture the memory space into multiple regions.
–
Same quantity of both DIMMs are required on each CPU.
– "x" must always be DIMM with more ranks than "z".
–
If both DIMMs have same number of ranks, "x" represents DIMMs with
higher capacity.
Main memory
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