HPE ProLiant DL340 Gen12 Memory

Genuine HPE DDR5 Smart Memory for the HPE ProLiant DL340 Gen12, new and refurbished, tested before shipping. This is a single-socket Intel Xeon 6 server with 16 DIMM slots on 8 memory channels, and the decision that matters most is how many slots you fill: one DIMM per channel keeps the memory at 6400 MT/s, two per channel drops it to 5200.

DL340 Gen12 Memory Specifications

• Type: HPE DDR5 Smart Memory Registered (RDIMM); all DIMMs must be DDR5, and HPE states its Smart Memory is required to reach the performance figures it publishes
• Slots: 16 in total — 8 channels with 2 DIMMs per channel on the single processor
• Speed: every kit listed is DDR5-6400; the server runs 6400 MT/s at one DIMM per channel and 5200 MT/s at two, and the maximum is also limited by the processor — HPE lists the 6710E, 6731E and 6746E at 5600 MT/s
• Maximum: 4TB, using sixteen 256GB quad-rank 3DS RDIMMs; HPE states that all processors listed support up to 4TB
• Kits listed: 16GB single-rank x8, 32GB dual-rank x8, 64GB, 96GB and 128GB dual-rank x4, and 256GB quad-rank x4 3DS, all EC8 Registered at CAS-52-52-52 (CAS-60-52-52 on the 256GB)
• Cooling rules: the high-performance fan kit is required with 9 DIMMs or more, and whenever 256GB DIMMs are used
• Protection: Advanced ECC, Adaptive Double DRAM Device Correction (enabled by default) and Memory Mirroring
• Ordering: the -B21 kits on this page are the stand-alone SKUs; the matching -F21 SKUs exist only for factory-integrated servers

Eight DIMMs is the line between 6400 and 5200 MT/s. The DL340 Gen12 runs its DDR5-6400 memory at 6400 MT/s with one DIMM per channel and 5200 MT/s with two, so eight modules across eight channels is the largest configuration that keeps full speed — 8 × 128GB reaches 1TB that way. The ninth DIMM also triggers HPE's requirement for six high-performance fans, as does any 256GB module, so plan the fans and the memory together.

How much memory can the DL340 Gen12 hold?

Eight modules is the practical sweet spot. HPE's population tables fill one DIMM per channel up to eight modules for both E-Core and P-Core processors, which is exactly the point where 6400 MT/s is still available, and 8 × 128GB reaches 1TB without a speed penalty. Past eight, every configuration runs at 5200 MT/s and needs six performance fans, so the ninth DIMM is a bigger decision than the sixteenth.

Choosing the Right DL340 Gen12 Memory

• Follow HPE's population order. E-Core processors support 1, 2, 4, 8 and 16 DIMM configurations; P-Core processors add a 12-DIMM step. Install DIMMs only after the processor is installed.
• Check the processor before promising 6400. HPE lists the 6710E, 6731E and 6746E E-Core parts at 5600 MT/s; every other Xeon 6 in HPE's tables is rated 6400, and two DIMMs per channel pulls any of them to 5200.
• Plan the fans with the DIMMs. Nine or more modules, or any 256GB module, requires the high-performance fan kit — six fans, and HPE does not allow standard and performance fans to be mixed.
• Mixing rules. x4 and x8 DIMMs may share a channel; 3DS and non-3DS modules may not, so the 256GB kit is not a top-up for a server full of 64GB or 128GB modules.
• Every kit is one DIMM. Eight 64GB modules is eight kits, not one boxed set.

Complete Your DL340 Gen12 Build

The processor sets the memory ceiling — see DL340 Gen12 processors before choosing a speed. For the rest of the server, browse DL340 Gen12 drives, storage controllers, networking adapters and power supplies, or the full DL340 Gen12 parts listing, where the fan kits live. Memory for the other Gen12 servers we stock is under HPE Gen12 server memory, including DL360 Gen12 memory and DL380 Gen12 memory. Background reading: maximum memory configurations for HPE ProLiant Gen12 servers, understanding memory rank and the importance of memory speed, plus the HPE parts by server model index.

DL340 Gen12 Memory FAQ

How much RAM does the DL340 Gen12 support?
4TB, using sixteen 256GB DDR5 3DS Registered DIMMs. HPE states that all the processors listed for the server support the full 4TB. The server has 16 DIMM slots across 8 memory channels on its single processor.

What type of memory does the DL340 Gen12 use?
HPE DDR5 Smart Memory Registered DIMMs (RDIMM). Every kit listed is DDR5-6400 EC8 Registered, from 16GB single-rank x8 to 256GB quad-rank 3DS. All DIMMs in the server must be DDR5.

What is the maximum memory speed of the DL340 Gen12?
6400 MT/s with one DIMM per channel, dropping to 5200 MT/s with two DIMMs per channel. The processor can lower that ceiling as well: HPE lists the 6710E, 6731E and 6746E at 5600 MT/s while every other Xeon 6 in its tables is rated 6400.

Why does a 16-DIMM DL340 Gen12 run at 5200 instead of 6400?
Because 16 DIMMs means two per channel, and HPE rates the server at 5200 MT/s at 2 DPC. Eight DIMMs, one per channel, is the largest configuration that holds 6400 MT/s, and 8 x 128GB reaches 1TB that way.

Do I need different fans when I add memory?
Yes, past a point. HPE requires the high-performance fan kit with 9 DIMMs or more, and whenever 256GB DIMMs are installed. Six fans are required per server and standard and performance fans cannot be mixed, so it is a six-kit change.

Can I mix DIMM capacities in a DL340 Gen12?
Within limits. HPE allows x4 and x8 DIMMs in the same channel, but does not allow 3DS and non-3DS modules on the same channel, so the 256GB 3DS kit cannot be added alongside 64GB or 128GB modules in one channel.

What is the difference between the -B21 and -F21 memory part numbers?
The -B21 kits are the stand-alone memory SKUs, which is what is sold here. HPE uses the corresponding -F21 SKU only when the DIMMs are factory-integrated into a new server.

✅ Looking for a specific DL340 Gen12 memory module? Browse our full selection below.

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