5
Memory
The PowerEdge R940xa support up to 48 DIMMs, with up to 6144GB of memory and speeds of up to 2666MT/s. The PowerEdge
940xa support registered (RDIMMs) and load reduced DIMMs (LRDIMMs) which use a buffer to reduce memory loading and provide
greater density, allowing for the maximum platform memory capacity. Also supports new persistent memory technologies like
NVDIMM-N.
The following list are key highlights for the PowerEdge R940xa memory modules:
•
The PowerEdge R940xa offers 48 Direct connect DDR4, no memory buffer
•
Memory speed at 2666MT/s
•
12 DIMMs per CPU, 6 Channels per CPU
•
Optimal memory capacity with 6 DIMM per CPU increment 192GB, 384GB, 768GB, 1.5TB and 3TB are optimized capacity
•
Only DDR4 RDIMMs, LR-DIMMs and NVDIMMs are supported
•
If DIMMs with mixed speed are installed, the memory will run at the lower frequency
•
NVDIMMs are only supported on the baseboard (12 max)
•
RDIMMs cannot be mixed with LR-DIMMs
•
NVDIMMs can be mixed with RDIMMS
•
NVDIMMs cannot be mixed with LR-DIMMs
Supported memory
The table below shows the supported memory technologies for the PowerEdge R940xa:
Table 7. Supported memory technologies
Feature
Description
DIMM type
•
RDIMM
•
LRDIMM
•
NVDIMM
Transfer speed
•
2666MT/s
•
2400MT/s
•
1866MT/s
Voltage
1.2V DDR4
Memory speed
The R940xa support memory speeds of 2666MT/s, 2400MT/s, 2133MT/s, and 1866MT/s depending on the DIMM types installed
and the configuration. 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 (specific CPU / DIMM configuration 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 2400MT/s memory
speed. he 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
20
