Dell EMC PowerEdge C6420 - Memory; Supported Memory; Memory Speed

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Memory
The C6420 supports up to 16 DIMMs, with speeds of up to 2666MT/s. The system supports registered (RDIMMs) and load reduced
DIMMs (LRDIMMs) which use a buer to reduce memory loading and provide greater density, allowing for the maximum platform
memory capacity. Unbuered DIMMs (UDIMMs) are not supported.
The maximum system population is 2TB (16 DIMM slots x128 GB DDR4 LRDIMM), however for best performance the system should
be populated to achieve a balanced conguration by populating 1 DIMM per channel. In a balanced conguration with maximum
capacity, 12 DIMM slots are populated for a total of 1.5TB memory using 128GB DIMMs.
Supported memory
The following table list the supported memory for the PowerEdge C6420 when using Cascade Lake processor:
Availability Density DIMM Type Dell PN Conguration DRAM Package
type
DIMM max speed Rated
voltage
Yes 8GB RDIMM 1VRGY 1Rx8 8Gb SDP 2666MT/s in Cascade
Lake processor
1.2V
Yes 16GB RDIMM TFYHP 2Rx8 8Gb SDP 2933MT/s 1.2V
Yes 32GB RDIMM 8WKDY 2RX4 8Gb SDP 2933MT/s 1.2V
Yes 64GB RDIMM W403Y 4Rx4 8Gb DDP 2933MT/s 1.2V
Yes 128GB LRDIMM 917VK 8Rx4 8Gb TSV 2666MT/s in Cascade
Lake processor
1.2V
Memory speed
The PowerEdge C6420 system supports memory speeds of 2933MT/s, 2666MT/s, 2400MT/s, 2133MT/s, and 1866MT/s depending
on the DIMM types installed and the conguration. All memory on all processors and channels run at the same speed and voltage. By
default, this speed will be the highest speed supported by the CPU and the DIMMs. For example both DIMMs and CPUs must be
capable of running at 2666MT/s in order for memory to run at 2666MT/s (specic CPU / DIMM conguration required). CPU SKUs
in the Platinum category support up to 2666MT/s memory speed while CPU SKUs in Gold and Silver category support up to 2400
MT/s memory speed. The operating speed of the memory is also determined by the maximum speed supported by the processor,
the speed settings in the BIOS, and the operating voltage of the system.
The table below lists the memory conguration and performance details for the Mercury, based on the quantity and type of DIMMs
per memory channel.
DIMM type
DIMM ranking Capacity DIMM rated voltage,
speed
1 DPC
RDIMM 1R / 2R 8GB, 16GB, 32GB DDR4 (1.2V), 2666 D: 2666
LRDIMM 4R 64GB DDR4 (1.2V), 2666 D: 2666
LRDIMM 8R 128GB DDR4 (1.2V), 2666 D: 2666
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