HPE ProLiant DL325 Gen11 review: An affordable liquid-cooled rack server with a massive core count

AMD's Gen4 EPYC CPUs deliver some incredible core counts allowing single-socket (1P) servers to offer a serious alternative to more costly dual-socket (2P) servers. The high TDP of the top EPYC models does present a problem for low-profile 1U rack servers though, as going up to the more thirsty models usually requires expensive open-loop water cooling.

HPE's ProLiant DL325 Gen11 neatly solves this conundrum as it's available with HPE's closed-loop liquid cooling system. This means you can put any Gen4 EPYC CPU you want in it, including the 128-core 2.25GHz 360W 9754 and the 96-core 2.55GHz 400W 9684X.

There's a lot more to this server as along with a high core competence, it supports up to 3TB of HPE's DDR5 SmartMemory and has plenty of expansion potential. Storage features are equally good as you can choose from LFF and SFF form factors, SAS, SATA, and NVMe devices, and even up to twenty EDSFF E3.S SSDs.

HPE ProLiant DL325 Gen11 review: Build and design

As you'd expect, HPE's chassis built quality is exemplary, and cracking the lid reveals a very tidy interior with easy access to all key components. The CPU socket is centrally mounted and flanked on each side by six DIMM slots.

The liquid cooling kit must be specified for CPUs with TDPs equal to or more than 320W and is required for the 64-core 3.1GHz AMD EPYC 9554P in our review system as this has a default 360W TDP. The components take up barely any room as the CPU cold plate has two coolant pipes routed directly to a full-width radiator mounted between the seven hot-plug cooling fans and the drive backplane.

The cold plate has an integral pump powered by a short cable from a board connector next to the CPU socket. The pipes look reassuringly sturdy and the coolant is a mix of purified water, ethylene, and corrosion resistant additives 

Note that the liquid cooling kit has a maximum usage limitation of five years after which it must be replaced by HPE at the customer's expense. The server includes a standard three-year warranty but for extra peace of mind it would be well worth extending this to five years

HPE ProLiant DL325 Gen11 review: Management and monitoring

HPE's iLO6 controller keeps a close eye on the liquid cooling module and if it detects any problems it can issue SNMP traps and email alerts. The Power & Thermal page provides more details on the cooling fans and their speeds and although noise levels are irritating, this server will most likely be in a dedicated room.

Along with a very informative web interface, the iLO6 clearly has platform security as a high priority. Along with HPE's Secure Start and 'silicon root of trust' firmware fingerprinting, the SPDM (Security Protocol and Data Module) feature authenticates all hardware components plus optional PCIe expansion cards and alerts you to 'hostile' devices.

All ProLiant Gen10 and Gen11 servers can connect directly to HPE's Compute Ops Management (COM) cloud service. Part of HPE's GreenLake platform, it provides complete server lifecycle management and remote integration with HPE's OneView on-premises management platform.

We run HPE's iLO Amplifier Pack in the lab as a Hyper-V VM which provides discovery, inventory, and compliance reporting for up to 10,000 Gen8, 9, 10, and 11 servers. It can send inventory and performance data to HPE's InfoSight cloud service which can now be accessed directly from the GreenLake portal.

HPE ProLiant DL325 Gen11 review: Storage and expansion

For a low-profile 1U rack server, the DL325 Gen11 offers a surprisingly good range of storage options. Our system came kitted out with the eight SFF drive backplane and a full house of SATA SSDs which can be bumped up to ten with an extra front dual-bay cage.

Other storage configurations are a four LFF drive backplane or a twenty EDSFF E3.S SSD version. The server supports up to four single-width or two double-width GPUs and in these configurations, you're still left with a single bay to the left which supports four SFF drives or eight EDSFF E3.S SSDs.

AMD's chipset doesn't offer any integrated RAID features so unless you intend to use software-managed arrays, you'll need to source one of HPE's controller cards. There are plenty to choose from including the Gen11 Tri-Mode PCIe adapters and OCP 3 versions with the top-dog SR932i-p supporting 24G SAS, SATA, and NVMe devices.

Our system was also supplied with HPE's NS204i-u Gen11 boot-optimised storage device which is worth considering if you want all your front bays free for data storage. Slipping into a dedicated bay and cabled directly to the motherboard, it presents two hot-plug M.2 NVMe SSDs at the rear and provides mirrored redundant storage for running an OS or hypervisor.

There's plenty of room for further expansion as the server has two risers each sporting PCIe Gen5 x16 slots with enough space in front of the primary slot for a full-height, full-length card. Underneath these you'll find two OCP 3 PCIe 5 slots which support HPE's 'o' RAID cards and a good range of network adapters with our system supplied with HPE's quad-port Gigabit module.

HPE ProLiant DL325 Gen11 review: Is it worth it?

The ProLiant DL325 Gen11 is a good value single-socket 1U rack server and with AMD's Gen4 EPYC CPUs in the driving seat, looks set to take on a wide range of enterprise workloads. The air-cooled version is a very capable system but HPE's closed-loop liquid cooling system adds extra versatility as it allows the server to support up to 400W TDP CPUs.

The liquid-cooled model on review is a great choice for virtualization tasks that require high core densities. It will also appeal to businesses that want to squeeze maximum processing power from their rack cabinets without heavy investment in open-loop water cooling systems.

HPE ProLiant DL325 Gen11 specifications