The Dell PowerEdge R750xa is a phenomenal 2U Rackmount server in the 15th generation of Dell Servers. It is a variant of the R750, that specializes in GPU-optimization. The “xa” in R750xa stands for Extreme Acceleration. This system is perfect High Performance Computing (HPC), Artificial Intelligence (AI), Machine Learning (ML), or Deep Learning (DL) applications. We will highlight some of the similarities and differences between the R750 and R750xa. We will also compare and contrast the different R750xa chassis options

R750 vs R750xa

From an outside view, the PowerEdge R750xa and R750 look the same, but they are different systems. They share a lot of the same features, but the R750xa is heavily focused on Graphics Card Optimization. The R750xa uses the same motherboard as the R750, but it has been reconfigured. The chassis of the R750xa is roughly 4 inches longer than the R750. The motherboard in the R750xa fills up this extra space, leaving space in the front for graphic cards to be installed. 4 double-wide or 6 single-wide GPUs are supported. Both the R750xa and the R750 have two CPU sockets that support up to 40 CPU cores each. They both also support 32 total DIMM slots. The R750xa is more limited when it comes to drive bay options and form factors. Only 2.5” drives can be used across all R750xa chassis.

Bay Counts

The Dell PowerEdge R750xa has two bay count options to choose from. There is a 6 Bay SFF option as well as an 8 Bay SFF options. For the 6 Bay SFF option, there is only one backplane option that allows you to attach six 2.5” NVMe drives to the backplane. For the 8 Bay SFF chassis, there are three backplane options to choose from. The first option allows you to install eight 2.5” SAS/SATA SSDs the backplane. The second backplane option for the 8 Bay SFF chassis allows you to plug in eight NVMe drives into the backplane. For the last options, you can plug in up to four 2.5” SAS/SATA drives and four 2.5” NVMe drives.

Chassis Rear and PCIe Slots

There are two total rear configurations for the R750xa. The first configuration has two x8 full-height PCIe slots, two x16 low-profile PCIe slots, a BOSS-S2 module, and an x8 OCP slot. The second rear configuration has two x16 low-profile PCIe slots, a BOSS-S2 module, and an x8 OCP slot. Both rear configurations include two RJ45 LOM ports, an RJ45 dedicated iDRAC port, two USB ports, a VGA port, and two hot-swap power supply bays. A total of two side-wide GPUs can be installed in the rear PCIe slots. Moving away from the rear, are four PCIe slots in the front, two on each side of the chassis. These PCIe slots can accept single-wide or double-wide GPUs.

The Dell PowerEdge R750xa server has two CPU sockets which both accept 3rd Generation Intel Xeon Scalable Processors. Each CPU socket supports up to 40 CPU cores, meaning that up to 80 cores can be installed!

When compared to the R750, the R750xa does not have as many storage options to pick from. There are to large form factor chassis for the R750xa, so 3.5” drives are not supported by this server. There is also no option to have 2.5” drive bays in the rear of the chassis. All chassis options accept 2.5” drives in the backplane. M.2 drives can be installed with the use of the BOSS-S2 module or BOSS-S1 card. The Dell PowerEdge R750xa supports the use of HDDs, SSDs, U.2s, M.2s, and uSDs. Supported drive interfaces are: SATA, SAS, and NVMe

Supported Drives

NVMe is a crazy faster technology used in storage devices that out-performs most non-NVMe drives. NVMe offers a major advantage in environments where speed is key! The R750xa has loads of NVMe support.

U.2 NVMe and Backplane NVMe

Some of the chassis for the R750xa has NVMe support built into the backplane. The 6 Bay SFF chassis supports NVMe drives in all six slots on the backplane For the 8 Bay SFF chassis, there are two backplane options that support NVMe drives. The first option supports NVMe in all eight drive bays. The second option supports NVMe in only four slots, while the other four slots support SAS/SATA SSDs.

M.2 NVMe

The Dell PowerEdge R750xa does not support NVMe M.2 drives. M.2 drives can still be used with the BOSS-S1 or BOSS-S2, but NVMe M.2 SSDs are not supported.

How Many Power Supplies does the R750xa Take?

The Dell PowerEdge R750xa server can hold up to two power supply units (PSU). Power supplies for the R750xa are hot-swap meaning that you can remove or add a power supply while the system is running. In order to do this, one PSU must remain within the system. This is useful in case one PSU in your server fails. The other power supply will keep the system running until you can get the bad one replaced.

Wattage Options

There are two power supply wattage options that are available for the PowerEdge R750xa. These options are: 1400W and 2400W. The lower wattage options that were available for the R750 cannot be used for this system. Because the R750xa is designed for resource intensive applications such as HPC, AI, ML, DL, Database analytics, VDI, and graphic workloads, this server needs all the power it can get. These applications demand a lot of power, which means they require high wattage power supplies.

Voltage

There is one voltage options for each wattage option. Each wattage comes in AC/240 HVDC. The types of connections that support this voltage are typically found in datacenters. If you are thinking about purchasing a Dell PowerEdge R750xa server, make sure the connection at your datacenter or lab supports the voltage of this power supply.

If you want to connect your server to the Internet, it will need some type of network card. You can use the integrated network ports that are built-in to the motherboard, however they only run at 1Gb/s and there are only two ports. To expand the networking capabilities of your R750xa, you can install an addition OCP network card. There is a built in x8 OCP 3.0 slot in the back of the server. You also have the ability to install PCIe network cards. We recommend using an OCP card since, it doesn’t take up a PCIe slot. There are both RJ45 and fiber options as well as 1GbE and 10GbE speeds to choose from.