Dell PowerEdge R940 Server

The Dell PowerEdge R940 server is perfect for automation. This 3U rackmount server has two different chassis options to choose from: 8 Bay SFF and 24 Bay SFF.

8 Bay SFF

The 8 Bay SFF chassis for the PowerEdge R940 accepts up to eight hot-swap 2.5" SAS/SATA drives and up to twelve NVMe PCIe SSDs. Drive plugged into the backplane are hot-swap, meaning that drives can be added or removed while the server is powered on. This is good in situations where a drive fails and you need to replace it, but your server can stay online.

24 Bay SFF

The 24 Bay SFF chassis is nearly identical to the 8 Bay SFF chassis. The 24 Bay SFF chassis supports up to twenty-four hot-swap 2.5" SAS/SATA drives and up to twelve NVMe PCIe SSDs. Just like the 8 Bay SFF chassis, the 24 Bay SFF chassis' backplane supports hot-swap drives, which allows you to add or remove drives while the system is running.

Chassis Rear

The chassis rear is identical across both chassis’ options. The rear includes twelve full-height PCIe slots, a network daughter card slot, a serial connector, a VGA port, two type A USB ports, a dedicated iDRAC LAN port, and two hot-swap power supply bays.

The Dell PowerEdge R940 server has four LGA3647 CPU sockets that accept 1st and 2nd generation Intel Xeon Scalable processors. A maximum of 28 cores per processor is allowed, meaning that the R940 can have a maximum of 112 CPU cores across all four CPU sockets.

DIMM slots & Memory Channels

The Dell PowerEdge R940 is a DDR4 based machine with 48 DIMM slots and 24 total memory channels. There are two system boards inside, that each have 24 DIMMs. Each memory channel consists of two DIMM slot.

Supported Memory Types

The Dell PowerEdge R940 server accepts ECC Registered (RDIMM), Load Reduced (LRDIMM), Non-volatile memory (NVDIMM), and Intel Optane DC Persistent Memory (DCPMM). It is important to not mix different memory types unless you are mixing LRDIMMs or RDIMMs with DCPMMs together. Mixing together other types can lead to issues such as boot failure.

Supported Memory Capacities

Module capacities of 8GB, 16GB, 32GB, 64GB, 128GB, 256GB, and 512GB. 128GB modules are only available as Load Reduced and Intel Optane PMem. 256GB modules are only available as Load Reduced and Intel Optane PMem. Lastly, 512GB modules are only available as Intel Optane PMem.

Max Configurations

With ECC Registered memory, the max RAM capacity that can be achieved is 3TB (3072GB) via 48 x 64GB RDIMMs. With Load Reduced Memory, the maximum RAM capacity that can be achieved is 6TB (6144GB) via a configuration of 48 x 128GB LRDIMMs. With Non-volatile memory, a max RAM capacity of 192GB can be reached via 12 x 16GB NVDIMMs. 64GB RDIMMs can be installed into the remaining 36 DIMMs slots, bringing the total RAM capacity to 2.4TB (2496GB). Finally for Intel Optane DC Persistent Memory, the maximum possible RAM capacity is 12.28TB (12288GB) via 24 x 512GB DCPMMs. 128GB LRDIMMs can be installed into the last 24 DIMM slots, bringing the total capacity to 15.36TB (15360GB).

Supported Memory Speeds

The Dell PowerEdge R940 supports module speeds of 2133MT/s, 2400MT/s, 2666MT/s, and 2933MT/s. 3200MT/s modules can be installed, but will clock down to the fastest possible speed for your server's configuration. The processor that you have installed will determine the fastest supported memory speed is for your configuration. For example, if you install a processor that has a max memory speed of 2666MT/s, and you install a 2933MT/s module, the module will operate at 2666MT/s.

The Dell R940 server accepts 2.5" SAS/SATA drives. There is no chassis option for the R940 to install 3.5" drives. Only 2.5" drives can be used with the R940. The total number of drives that can be installed into your system depends on the chassis that you have. If you have an 8 Bay SFF chassis, up to eight 2.5" SAS/SATA hard drives and/or solid state drives can be installed. If you have a 24 Bay SFF chassis, up to twenty-four 2.5" SAS/SATA hard drives and/or solid state drives can be installed.

Supported Drives (2.5")

How Many Power Supplies does the R940 Support?

The Dell PowerEdge R940 server supports up to two hot-swap power supply units (PSUs). Because power supplies for this system are hot-swap, PSUs can be added or removed while the server is powered on, as long as one unit remains plugged into the system.

Power Supply Options

In order to connect your R940 server to the Internet, you will need some type of Network Interface Card (NIC). The PowerEdge R940 accepts two NIC form factors: Daughter cards and PCIe cards. In the rear of the chassis, there is a dedicated slot, specifically for network daughter cards. Along with the daughter card, you can install multiple PCIe network cards if needed.