Maximum Memory Configurations for HPE ProLiant Gen12 Servers

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The maximum memory configuration of an HPE ProLiant Compute Gen12 server reaches 8TB on a dual-socket Intel Xeon 6 system like the DL380 Gen12, while a single-socket AMD EPYC server like the DL325 Gen12 packs up to 6TB into one processor — and as with every generation, the supported memory type, speed, and capacity depend on which processor your server runs. Gen12 also introduces faster DDR5 (up to 6400 MT/s) and support for a new high-bandwidth memory type, MRDIMM. This guide details the maximum memory configuration for every HPE ProLiant Gen12 server, organized by processor family, so you can plan a full-capacity upgrade without compatibility surprises.

Maximum Memory by HPE ProLiant Gen12 Model

The table below summarizes the maximum memory configuration of each mainstream HPE ProLiant Compute Gen12 server. The "Max Speed" column shows the top DDR5 RDIMM speed at one DIMM per channel; speeds step down when both slots in a channel are populated (see notes).

Server Model	CPU Family	Sockets	DIMM Slots	Channels / CPU	Memory Type	Max Memory	Max Speed (MT/s)
DL320 Gen12	Intel Xeon 6	1	16	8	DDR5 RDIMM	4TB	6400
DL340 Gen12	Intel Xeon 6	1	16	8	DDR5 RDIMM	4TB	6400
DL360 Gen12	Intel Xeon 6	2	32	8	DDR5 RDIMM	8TB	6400
DL380 Gen12	Intel Xeon 6	2	32	8	DDR5 RDIMM	8TB	6400
ML350 Gen12	Intel Xeon 6	2	32	8	DDR5 RDIMM	8TB	6400
DL325 Gen12	AMD EPYC 9005	1	24	12	DDR5 RDIMM	6TB	5200
DL345 Gen12	AMD EPYC 9005	1	24	12	DDR5 RDIMM	6TB	5200

Notes: The largest module is 256GB across all of these servers. On the Intel Xeon 6 servers, memory runs at 6400 MT/s at 1 DIMM per channel and 6000 MT/s at 2 DIMMs per channel, and the boards also support MRDIMM (see below). The AMD EPYC servers use a 24-slot (2 DIMMs per channel) design that trades speed for capacity: 5200 MT/s at 1 DIMM per channel, dropping to 4400 MT/s when all 24 slots are filled. Two further Gen12 models — the GPU-focused DL380a and the NVIDIA Grace Hopper DL384 — are covered separately below.

The Gen12 Memory Families

Unlike Gen11, whose maximum memory configurations spanned three memory architectures (including unbuffered UDIMM entry servers), the current Gen12 lineup is built entirely on ECC Registered (RDIMM) memory across two processor families:

Intel Xeon 6 (RDIMM, 8 channels per CPU) — the mainstream rack and tower servers (DL320, DL340, DL360, DL380, ML350). These use DDR5 ECC Registered (RDIMM) memory at up to 6400 MT/s and reach up to 8TB on the dual-socket models. Their system boards also support MRDIMM, a new higher-bandwidth memory type.
AMD EPYC 9005 (RDIMM, 12 channels per CPU) — the single-socket EPYC servers (DL325, DL345). With 5th Gen AMD EPYC "Turin" processors scaling to 192 cores, these servers use a 24-slot, 2-DIMM-per-channel layout to deliver up to 6TB of DDR5 from a single processor.

No Gen12 server uses Load-Reduced (LRDIMM) or non-ECC memory, and there is currently no unbuffered (UDIMM) entry model in the Gen12 family — for those, the Gen11 ML30 and DL20 remain HPE's entry-level options.

What's New in Gen12 Memory

Gen12 brings three notable memory changes over Gen11:

Faster DDR5 (up to 6400 MT/s). The Intel Xeon 6 servers raise the top RDIMM speed from 5600 MT/s on Gen11 to 6400 MT/s, improving memory bandwidth for data-intensive and AI workloads.
MRDIMM support (up to 8800 MT/s). The Intel Xeon 6 system boards support Multiplexed Rank DIMM (MRDIMM), a new high-bandwidth memory type that runs at up to 8800 MT/s. MRDIMM is limited to one DIMM per channel and to P-core processors. Note that HPE has not yet released MRDIMM kits into the standard ProLiant Compute portfolio — availability requires qualification through an HPE representative — so DDR5 RDIMM remains the memory you'll buy for these servers today.
Higher single-socket capacity on AMD. The AMD EPYC Gen12 servers double the previous generation's single-socket capacity to 6TB by moving to a 24-DIMM (2 DIMMs per channel) design.

Memory Speed Depends on Your Processor — and DIMM Layout

On every Gen12 server, the maximum memory speed is set by the processor and the memory configuration, not the DIMM alone. Keep speed grades consistent, since the system runs all installed memory at the speed of the slowest module. By family:

Intel Xeon 6 (DL320, DL340, DL360, DL380, ML350 Gen12): up to 6400 MT/s at 1 DIMM per channel, 6000 MT/s at 2 DIMMs per channel, with DDR5 RDIMM. MRDIMM can reach 8800 MT/s (1 DIMM per channel, P-core CPUs) where qualified.
AMD EPYC 9005 (DL325, DL345 Gen12): up to 5200 MT/s at 1 DIMM per channel, 4400 MT/s with all 24 slots populated. Because these servers are wired for 2 DIMMs per channel to maximize capacity, the memory clock is lower than on the Intel Gen12 servers even when fewer DIMMs are installed — a deliberate trade of speed for the ability to reach 6TB on a single socket.

The practical takeaway: choose the Intel Xeon 6 servers when memory bandwidth is the priority, and the AMD EPYC servers when maximum capacity and core count per socket matter most. The exact speed also depends on the specific CPU model, so check your processor's specifications or HPE iLO before ordering.

Supported DIMM Types

Every mainstream Gen12 server uses DDR5 ECC Registered (RDIMM) memory, available in 16GB, 32GB, 64GB, 128GB, and 256GB modules (256GB is the largest qualified DIMM and is required to reach the headline capacities). The Intel Xeon 6 boards additionally support MRDIMM, though those kits are not yet generally available. Two rules apply across the line: Load-Reduced DIMMs (LRDIMMs) are not used in any Gen12 server, and non-ECC memory is not supported. For best performance, use uniform DIMMs of the same capacity and rank across all channels.

Maximum Memory Configurations by Server Family

Reaching the maximum memory configuration means populating every DIMM slot with the largest qualified 256GB module. How you get there depends on the family:

Intel Xeon 6 Servers (up to 8TB)

The dual-socket DL360, DL380, and ML350 Gen12 each reach their 8TB maximum by populating all 32 DIMM slots with 256GB RDIMMs — 16 modules per processor across 8 channels, 2 DIMMs per channel. Both processors must be installed to access all 32 slots; a single CPU exposes 16 slots and up to 4TB. The single-socket DL320 and DL340 Gen12 reach 4TB with 16 × 256GB modules.

AMD EPYC 9005 Servers (up to 6TB)

The single-socket DL325 and DL345 Gen12 reach a 6TB maximum with 24 × 256GB modules across 12 channels at 2 DIMMs per channel. This is the standout capacity story of the Gen12 line: 6TB from a single processor. Just plan around the speed trade-off — a fully populated 24-DIMM configuration runs at 4400 MT/s, so if your workload favors bandwidth over raw capacity, a partially populated (1 DIMM per channel) configuration at 5200 MT/s may serve better.

One planning note for maximum-capacity builds on either family: the largest 256GB modules and fully populated configurations often require a high-performance or redundant fan configuration. Check your server's QuickSpecs or population guide before finalizing an 8TB or 6TB build.

Specialized Gen12 Servers: DL380a and DL384

Two Gen12 models are purpose-built for AI and handle memory differently:

HPE ProLiant Compute DL380a Gen12 — a 4U, dual-socket Intel Xeon 6 server built for GPU-accelerated AI inference, supporting up to ten double-wide or sixteen single-wide GPUs. It uses standard DDR5 RDIMM like the other Intel Xeon 6 servers, but its layout prioritizes GPU density.
HPE ProLiant Compute DL384 Gen12 — the first HPE ProLiant rackmount server built on the NVIDIA GH200 Grace Hopper Superchip. It uses on-package LPDDR5X memory tied to the Arm-based Grace CPUs (with HBM3e on the Hopper GPUs), not standard DDR5 DIMMs, so it is not a conventional memory-upgrade platform.

Memory Installation & Population Rules

Whatever the family, begin by filling the white-labeled DIMM slot in each channel, use identical modules across channels, and on dual-socket servers balance memory evenly across both processors. Supported DIMM quantities and population order differ by CPU family, so use HPE's Gen12 population guide for your platform:

Intel Xeon 6 Gen12 servers: HPE Server Memory Population Rules — Intel Xeon 6 (PDF)
AMD EPYC 9005 Gen12 servers: HPE Server Memory Population Rules — AMD EPYC 9005 (PDF)

How to Upgrade Gen12 Server Memory

Confirm your platform and CPU. Identify whether your server uses Intel Xeon 6 or AMD EPYC 9005, since that sets the channel count, supported speed, and maximum capacity.
Power down and prepare. Shut down the server completely, unplug all power sources, and wait at least 30 seconds before opening the chassis.
Access the DIMM slots. Open the server cover and locate the memory slots beside the processor(s).
Verify compatibility. Make sure the new modules are DDR5 ECC RDIMM at the correct speed and capacity for your server, and that they match the existing modules where possible.
Install the modules. Populate the white-labeled slots first to distribute memory evenly across channels, and press each module firmly until the latches click into place.

Choosing the Right Memory Module

To ensure a guaranteed-compatible, stable upgrade, confirm each of the following before you buy:

Module type — DDR5 ECC Registered (RDIMM) for all current mainstream Gen12 servers.
Speed grade — matched to your platform (up to 6400 MT/s on Intel Xeon 6 servers, up to 5200 MT/s on AMD EPYC servers).
Capacity — within your server's per-DIMM (up to 256GB) and total limits.
HPE part number — validated for your specific server model.

HPE DDR5 Smart Memory is required to reach the rated performance on these platforms. If you're unsure which module fits your configuration, contact our HPE specialists for a guaranteed-compatible recommendation.

Frequently asked questions

What is the maximum memory in an HPE ProLiant Gen12 server?

It depends on the processor. Dual-socket Intel Xeon 6 servers (DL360, DL380, and ML350 Gen12) reach 8TB using 32 × 256GB DDR5 RDIMMs. Single-socket AMD EPYC 9005 servers (DL325 and DL345 Gen12) reach 6TB using 24 × 256GB RDIMMs. The single-socket Intel models (DL320 and DL340 Gen12) reach 4TB.

What memory speed do HPE Gen12 servers run at?

Intel Xeon 6 servers run DDR5 RDIMM at up to 6400 MT/s at one DIMM per channel and 6000 MT/s at two DIMMs per channel. AMD EPYC 9005 servers run at up to 5200 MT/s at one DIMM per channel, dropping to 4400 MT/s when all 24 slots are populated. The system runs all installed memory at the speed of the slowest module.

What type of memory do HPE Gen12 servers use?

Every mainstream Gen12 server uses DDR5 ECC Registered (RDIMM) memory, available in 16GB through 256GB modules. Load-Reduced (LRDIMM) and non-ECC memory are not supported, and there is currently no unbuffered (UDIMM) entry model in the Gen12 family.

Do HPE Gen12 servers support MRDIMM?

The Intel Xeon 6 system boards support MRDIMM, a newer high-bandwidth memory type, at one DIMM per channel on P-core processors. However, HPE has not yet released MRDIMM kits into the standard ProLiant Compute portfolio, so DDR5 RDIMM is the memory to buy for these servers today.

Why is AMD EPYC Gen12 memory slower than the Intel servers?

The AMD EPYC servers (DL325 and DL345 Gen12) use a 24-slot, two-DIMM-per-channel design to deliver 6TB from a single socket. That layout trades clock speed for capacity, so memory runs at 5200/4400 MT/s rather than the Intel servers' 6400 MT/s — a deliberate exchange of bandwidth for maximum single-socket capacity.

Do I need both processors installed to reach maximum memory?

On the dual-socket Intel Xeon 6 servers, yes — both CPUs must be installed to access all 32 DIMM slots and the full 8TB; a single processor exposes 16 slots and up to 4TB. The AMD EPYC Gen12 servers are single-socket and reach their 6TB maximum with one processor.

How do I reach the full 8TB or 6TB maximum?

Populate every DIMM slot with the largest qualified 256GB RDIMM and follow HPE's memory population rules for your CPU family. Note that fully populated maximum-capacity builds often require a high-performance or redundant fan configuration, so check your server's QuickSpecs before finalizing.

Summary

The maximum memory configuration of an HPE ProLiant Compute Gen12 server depends on its processor family. The Intel Xeon 6 servers (DL320, DL340, DL360, DL380, ML350 Gen12) use DDR5 RDIMM at up to 6400 MT/s and scale to 8TB on dual-socket models, with MRDIMM support on the horizon. The AMD EPYC 9005 servers (DL325, DL345 Gen12) deliver a remarkable 6TB from a single socket using a 24-DIMM design, trading some memory speed (5200/4400 MT/s) for that capacity. To reach full capacity, confirm your platform, populate every channel with 256GB RDIMMs, match the speed grade to your CPU, and follow HPE's Gen12 population guide for your server. Browse our full HPE Gen12 server memory selection to find guaranteed-compatible modules for your model.

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