Home > Servers > PowerEdge Components > White Papers > Memory Population Rules for 3rd Generation Intel Xeon Scalable Processors on PowerEdge Servers > Identical CPU and DIMM parts
Although Dell Technologies does allow for DIMM mixing (up to two different DIMM PNs in a system), and this would still be considered a balanced configuration, it is good practice to have identical DIMMs used across all DIMM slots. If memory DIMMs are installed with different speeds (they must have the same rank, capacity and DIMM type) then they will operate at the speed of the slowest DIMM. This principle applies to the processors as well; multi-socket Intel systems shall be populated with identical CPUs.