The HPE ProLiant DL380 Gen10 has 24 DIMM slots and takes DDR4 ECC registered memory only. The DL380 Gen10 max memory is 3 TB, but only with 128GB LRDIMMs and CPUs that allow 1.5 TB each. Your CPU also sets the speed, anywhere from 2133 to 2933 MT/s. And RDIMMs and LRDIMMs never mix.

One catch: the Gen10 and the Gen10 Plus sound alike, but they take different memory. This guide covers DL380 Gen10 memory first, then shows where the Gen10 Plus differs. You'll get HPE's limits by CPU, the right HPE DDR4 server memory kits, and the slots to fill for an upgrade. The numbers come from HPE's QuickSpecs (its spec sheets) and memory papers, checked in October 2026. The bandwidth figures are our own math.

DL380 Gen10 memory at a glance

Both servers take registered DDR4 with ECC, as RDIMM (registered) or LRDIMM (load-reduced). Our ECC vs non-ECC RAM guide explains what ECC does. Here is how the two servers compare.

The figures come from HPE's DL380 Gen10 QuickSpecs and Gen10 Plus QuickSpecs. HPE now lists both as retired, so treat them as archives. MT/s means million transfers per second. Peak bandwidth is channels times speed times 8 bytes, which is our math.

DL380 Gen10 max memory: what it takes to reach 3 TB

HPE lists 3 TB for the DL380 Gen10. That takes 24 LRDIMMs of 128GB each. With RDIMMs, the top is 1.5 TB, using 24 modules of 64GB.

Your CPUs can lower those numbers, since each CPU has its own limit. HPE staff put it this way in a community thread: "Maximum memory per socket is dependent on processor selection." Per the QuickSpecs, a standard 1st Gen chip holds 768 GB, and a standard 2nd Gen chip holds 1 TB. The M models hold more, at 1.5 TB on 1st Gen and 2 TB on 2nd Gen. The 2nd Gen L models list 4.5 TB.

Now the math. Three TB across two CPUs is 1.5 TB each. A standard chip can't hold that, so you need M or L chips to fill all 24 slots with 128GB modules. The letter sits in the CPU name, as in the Platinum 8276M and 8276L. Two standard 2nd Gen chips cap the server at 2 TB, no matter how many slots you fill.

An L chip lists 4.5 TB, but two of them won't give you 9 TB. The board has only 12 slots per CPU, so with standard DDR4 modules the slots stop you at 3 TB. Intel Optane persistent memory is a separate path. It works on select 2nd Gen chips only, it can raise the total, and it holds memory speed to 2666 MT/s.

Memory speed on the DL380 Gen10: your CPU decides

The CPU sets the speed, not the module. A faster module just runs at the CPU's rate. HPE's speed tables list these rates for the DL380 Gen10.

One quirk: the 1st Gen Gold 5122 runs at 2666. The speed stays the same with one or two modules per channel, for both RDIMMs and LRDIMMs. So a 2933 module in a Silver 4214 server runs at 2400, and the extra rating goes unused.

Each CPU has six channels. At 2666 MT/s, they give 128 GB/s per CPU, and at 2933 MT/s they give 140.8 GB/s.

HPE DDR4 server memory: which RAM fits a DL380 Gen10

HPE offers its own tested modules as Smart Memory. It says you need DDR4 Smart Memory to reach the memory performance it lists. Three rules keep an upgrade on track.

• One module type. HPE does not support mixing RDIMMs and LRDIMMs. On the Gen10, RDIMMs run from 8GB to 64GB, and LRDIMMs come in 64GB and 128GB.
• One kit family. HPE's population paper says mixing sizes at the same speed costs no performance, and mixed speeds run at the lowest rate. Even so, HPE staff told one forum poster that mixing 2666 and 2933 kits is not supported. They also said a 2933 kit is not supported on a 1st Gen Gold 5115. So pair 2666 kits with 1st Gen chips and 2933 kits with 2nd Gen.
• No Gen9 modules. The same paper says Smart Memory from earlier server generations is not compatible. One owner who tried Gen9 modules saw iLO fail to authenticate them and turn Smart Memory off. HPE staff said the part was not in the Gen10 memory matrix.

Here are common HPE kits for the DL380 Gen10, with their option numbers. The last row is the module behind the 3 TB build.

CPU Republic lists each one as an HPE DDR4 ECC RDIMM or LRDIMM kit. For more sizes, see our server memory range.

HPE ProLiant Gen10 RAM upgrade: steps and which slots to fill

An HPE ProLiant Gen10 RAM upgrade goes best when you work through these steps one by one.

1. Check your CPU. Read the model in iLO, HPE's built-in management tool. Intel's rule is short: "The second digit indicates the processor generation." So a Gold 6230 is 2nd Gen, and a Gold 6338 is 3rd Gen.
2. Read your labels. Take 32GB 2Rx4 PC4-2933Y-R. That is a 32GB dual-rank module with x4 chips. PC4 means DDR4, and 2933 is the speed. Y is a timing code. The last letter is the type, with R for RDIMM and L for LRDIMM.
3. Pick matching kits. Keep the same type, and choose a speed that fits your CPU, using the tables above.
4. Power down. Turn the server off and unplug the power cords before you touch a slot.
5. Fill the slots. Use the slot table below. White slots go first in each channel. Give both CPUs the same setup. If you mix sizes, put the module with more ranks in the white slot.
6. Check iLO. After boot, it should show the new total and no memory warnings.

These slot numbers come from HPE's population paper. They apply per CPU on the DL380 Gen10.

Eight modules count as balanced, yet HPE says they give 33% less bandwidth than six, because they leave two channels empty. HPE also says to avoid unbalanced counts: 5, 7, 9, 10 and 11 per CPU. In its worst case, part of the memory delivered a third of the balanced throughput, or less.

DL380 Gen10 vs Gen10 Plus: what changes for memory

Not sure which server you have? Use the second-digit rule from step 1. A 1 or 2 means a Gen10, and a 3 means a Gen10 Plus.

The Gen10 Plus moves to 3rd Gen Xeon chips, and the memory changes with them. Intel lists the Xeon Gold 6230 with six channels at DDR4-2933. It lists the Xeon Gold 6338 with eight channels at DDR4-3200. That is the main gap: more channels and a faster bus. Speed still follows the CPU. HPE's tables list 3200 MT/s on Platinum and Gold 83xx and 63xx, 2933 on Gold 53xx, and 2666 on Silver 43xx.

Capacity gets simpler. HPE says all Gen10 Plus processors support up to 6 TB each. Sixteen 256GB 3DS (3D stacked) modules make 4 TB per CPU, so the slots run out before the chip does.

Two rules matter here. HPE supports DDR4-3200 kits only with 3rd Gen chips, so skip them for a Gen10. And 3DS and non-3DS modules can't mix. HPE also says to pick DIMMs in even quantities, since an odd count leaves memory unbalanced. For the best bandwidth, fill all eight channels on each CPU.

Don't assume modules swap between the two. Check HPE's kit list for your model first.

DL380 Gen10 memory FAQ

What is the max memory for the DL380 Gen10?

HPE lists 3 TB, using 24 LRDIMMs of 128GB. With RDIMMs, the top is 1.5 TB. Your CPUs can lower both numbers. With one CPU, halve them.

How many DIMM slots does the DL380 Gen10 have?

It has 24 slots, 12 per CPU. A one-CPU server can use only its own 12.

What memory speed does the DL380 Gen10 support?

Up to 2933 MT/s on top 2nd Gen chips and up to 2666 MT/s on top 1st Gen chips. Lower-tier chips run slower, down to 2133 MT/s on Bronze.

Can I mix RDIMM and LRDIMM in a DL380 Gen10?

No. HPE does not support it. Pick one type for the whole server.

Can I mix different module sizes?

Yes, if the type and speed match. HPE says mixing sizes at the same speed costs no performance. Put the module with more ranks in the white slot.

Can I use non-HPE RAM in a DL380 Gen10?

HPE tests and supports its own Smart Memory kits. Other brands may work, but HPE doesn't promise it. Check the part number against HPE's list first.

Does the DL380 Gen10 use DDR5?

No. It uses DDR4 only. Our DDR4 vs DDR5 server memory guide explains when each makes sense.

What is the memory difference between the Gen10 and Gen10 Plus?

The Gen10 Plus has 32 slots, eight channels per CPU, DDR4-3200 and up to 8 TB. The Gen10 has 24 slots, six channels, DDR4-2933, and up to 3 TB.

Check the CPU first, then match the kit

Start with your CPU, because it sets both the speed and the memory limit. Then match the module type and fill the slots in HPE's sequence. CPU Republic carries HPE DDR4 ECC RDIMM and LRDIMM kits in its server memory range. If you're unsure which kit fits your server, contact CPU Republic with your CPU model and the label on one module. Running Dell servers too? Our Dell PowerEdge memory guide covers the R640, R740, and R750.