Dell EMC PowerEdge R840 review: A pint-sized powerhouse

Dell EMC delivers a small rack server with a huge Xeon Scalable heart

IT Pro Verdict

The PowerEdge R840 is a rack-dense 4P Xeon Scalable powerhouse with a big memory capacity and a highly versatile storage arrangement


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    Low profile 2U chassis; 4P Xeon Scalable platform; 6TB memory capacity; Up to 24 NVMe SSDs; Slick iDRAC9; Good expansion potential


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    A year down the line and OpenManage Enterprise is still in development

Designed to munch through demanding tasks such as artificial intelligence, machine learning and database analytics, Dell EMC's PowerEdge R840 packs a mighty package into a slim-line 2U rack chassis. Its impressive hardware portfolio aims to get the most out of your rack infrastructure as it supports quad Xeon Scalable CPUs and a whopping 6TB of DDR4 memory.

There's more, as it supports up to twelve high-performance NVDIMM-N modules, has six PCI-Express (PCIe) expansion slots and can handle two double-width GPUs or full-height FPGAs (field programmable logic gates). Storage is high on its agenda too, as there's room for a total of 26 SFF drives and all 24 front bays can be populated with NVMe SSDs.

It's a very different beast to its predecessor, the R830. Along with a radically revamped internal design, the R840 offers twice the memory capacity, a 27% increase in CPU cores and a 62.5% boost in drive bays.

Dell EMC PowerEdge R840: Design

Cracking the lid reveals a new internal design as Dell EMC has done away with the optional PEM (processor expansion module). The R840 uses the same motherboard as the equally new PowerEdge R940xa which presents all four CPU sockets.

Good thermal design allows the R840 to support all Xeon Scalable models right up to the 28-core Platinums. The four sockets are flanked by 48 DIMM slots and to realize the maximum 6TB capacity, you'll need to specify 'M' designated Xeon Scalable CPUs which support 1.5TB per socket.

Our system is 6TB-capable as it came with a tasty quartet of 18-core 2.3GHz Gold 6140M CPUs. The price we've shown also includes a healthy 384GB of DDR4 memory with the 6140M CPUs supporting their highest 2,666MHz speed.

Cooling is handled by a bank of six fan modules arranged behind the drive backplane. These are all hot-pluggable and for easier access to the backplane, the whole fan tray can be easily released and removed.

Dell EMC PowerEdge R840: Storage versatility

The R840 has been designed to offer maximum storage flexibility where base units start with an 8-drive SAS/SATA backplane. This can be cabled directly to the motherboard's pair of SATA ports or to a PERC RAID card to bring SAS into play.

We have the SAS3 expander board and 24-drive active backplane which also has six dual-port PCIe connectors. These are cabled to the corresponding motherboard ports and the server's universal drive bays allow various mixes of SAS/SATA drives and NVMe SSDs to be implemented.

The 24 NVMe option requires four CPUs plus a special backplane and supports dual GPU configurations. You can add a dual-drive SAS/SATA cage at the rear - although this negates GPU support and also reduces the number of available PCIe slots.

RAID options start with the embedded PERC S140 chip which supports SATA drives plus stripes, mirrors and RAID5 arrays. Dell EMC offers a good choice of PERC RAID controllers and our system was supplied with an H740P card which occupies one vertical PCIe slot and comes with 8GB of battery-protected NVRAM cache.

Dell EMC PowerEdge R840: Remote management

Remote management doesn't get any better: the R840 sports Dell EMC's latest iDRAC9 chip along with a dedicated management port. It presents a smart HTML5 web console packed to the gills with valuable information about all critical hardware components.

Supply chain security can be assured as firmware packages are cryptographically signed and storage can be safely wiped using the iDRAC9 System Erase feature. The System Lockdown mode also stops users changing any server configuration settings.

The OpenManage Essentials software is due to be replaced by OpenManage Enterprise. We run the latter as a Hyper-V VM in the lab where it presents plenty of management features and operational data but it still hasn't been updated beyond the Tech Release that was launched a year ago.

Data centres will approve of the optional Quick Sync 2 module. Pressing the button under the system ID LED on the left rack ear activated Bluetooth allowing us to connect our iPad to the server via the OpenManage Mobile (OMM) iOS app and view all server information, alerts and health status.

Dell EMC PowerEdge R840: Power and expansion

Our server was supplied with dual, redundant 1100W Platinum hot-plug PSUs and other options include 750W, 1600W, 2000W and 2400W PSUs. Choose your CPUs carefully if power usage is a concern as the top-end models can be thirsty.

The 6140M CPUs in our system have a 140W TDP and we measured the R840 drawing 147W with Windows Server 2016 in idle but peaking at 810W with all 72 cores under maximum load. The R940 we exclusively reviewed recently had four 105W TDP Gold 5122 CPUs which pulled 145W in idle but peaked at a much lower 510W.

GPU cards are installed in the PCIe risers and the air shroud has all required power cables ready and waiting. If you fit these, you'll need a minimum of dual 1100W PSUs, which must be set to non-redundant mode.

A dedicated slot at the rear is provided for Dell EMC network daughter cards (NDCs). We have the basic quad Gigabit module but other options include dual 10GBaseT/1GbE, quad 10GbE and dual 25GbE NDCs.

Dell EMC PowerEdge R840: Verdict

It may have a low profile rack chassis but everything else about the PowerEdge R840 is big, making it a great choice for enterprises that want to maximize their data centre real estate. It offers high-performance 4P Xeon Scalable processing out of the box, has a big 6TB memory capacity and delivers the highest NVMe SSD density for a 2U rack server.


The PowerEdge R840 is a rack-dense 4P Xeon Scalable powerhouse with a big memory capacity and a highly versatile storage arrangement

Chassis: 2U rack

CPU: 4 x 2.3GHz 18-core Xeon Gold 6140M

Memory: 384GB 2,666MHz ECC DDR4 RDIMM (max 6TB)

Storage bays: 24 x SFF hot-swap (max 26)

RAID: Dell PERC H740P SAS3 with 8GB NVRAM cache/BBU

Storage included: 2 x 900GB SAS3 15K SFF HDD

Array support: RAID0, 1, 10, 5, 6, 50, 60

Network: 4 x Gigabit daughter card

Expansion: 6 x PCI-e 3.0 slots

Power: 2 x 1100W Platinum hot-swap PSUs

Cooling: 6 x hot-plug fans

Management: Dell iDRAC9 Enterprise, Quick Sync 2

Warranty: 3Yr ProSupport Plus and 4hr Mission Critical

Dave Mitchell

Dave is an IT consultant and freelance journalist specialising in hands-on reviews of computer networking products covering all market sectors from small businesses to enterprises. Founder of Binary Testing Ltd – the UK’s premier independent network testing laboratory - Dave has over 45 years of experience in the IT industry.

Dave has produced many thousands of in-depth business networking product reviews from his lab which have been reproduced globally. Writing for ITPro and its sister title, PC Pro, he covers all areas of business IT infrastructure, including servers, storage, network security, data protection, cloud, infrastructure and services.