HP Server RAM — Complete ProLiant Memory Upgrade Guide for 2026
Find the right HP ProLiant server memory. DDR3 vs DDR4 vs DDR5, ECC registered vs LRDIMM, compatible part numbers for DL360, DL380, DL560, and ML350 servers.
HP Server Memory — Why It Matters
Server memory is the single most impactful upgrade you can make to an HP ProLiant server. Adding RAM directly increases the number of virtual machines you can run, the size of databases you can cache, and the overall responsiveness of every application. Unlike desktop PCs, servers require specific memory types — ECC Registered (RDIMM) or Load-Reduced (LRDIMM) — that provide error correction and higher reliability for 24/7 operation.
HP brands their memory modules as "HPE SmartMemory" and charges a significant premium over third-party equivalents. The good news: Samsung, Hynix, and Micron manufacture the actual DRAM chips inside every HP module. Third-party server memory will generally boot and run in ProLiant servers.
HP ProLiant Memory Compatibility Chart
| Server Generation | CPU Platform | Memory Type | Max Speed | Max Capacity |
|---|---|---|---|---|
| DL380 Gen10 Plus | Intel Xeon 3rd Gen | DDR4 RDIMM/LRDIMM | 3200MHz | 8TB (32x 256GB) |
| DL380 Gen10 | Intel Xeon Scalable | DDR4 RDIMM/LRDIMM | 2933MHz | 3TB (24x 128GB) |
| DL380 Gen9 | Intel Xeon E5-2600 v3/v4 | DDR4 RDIMM/LRDIMM | 2400MHz | 3TB (24x 128GB) |
| DL380p Gen8 | Intel Xeon E5-2600 v1/v2 | DDR3 RDIMM/LRDIMM | 1866MHz | 768GB (24x 32GB) |
| DL360 Gen10 | Intel Xeon Scalable | DDR4 RDIMM/LRDIMM | 2933MHz | 3TB (24x 128GB) |
| DL360 Gen9 | Intel Xeon E5-2600 v3/v4 | DDR4 RDIMM/LRDIMM | 2400MHz | 3TB (24x 128GB) |
| DL360p Gen8 | Intel Xeon E5-2600 v1/v2 | DDR3 RDIMM/LRDIMM | 1866MHz | 768GB (24x 32GB) |
| ML350 Gen10 | Intel Xeon Scalable | DDR4 RDIMM/LRDIMM | 2933MHz | 3TB (24x 128GB) |
| DL560 Gen10 | Intel Xeon Scalable (4-socket) | DDR4 RDIMM/LRDIMM | 2933MHz | 6TB (48x 128GB) |
RDIMM vs LRDIMM — Which Should You Buy?
RDIMM (Registered DIMM) is the standard choice for most HP servers. Available in 8GB, 16GB, 32GB, and 64GB capacities. The register buffer on each module reduces electrical load on the memory controller, allowing servers to support many DIMM slots.
LRDIMM (Load-Reduced DIMM) uses a memory buffer that further reduces electrical load, enabling higher capacities per module — 64GB, 128GB, and 256GB. LRDIMMs are essential when you need maximum total memory.
| Feature | RDIMM | LRDIMM |
|---|---|---|
| Capacity | 8-64GB per module | 64-256GB per module |
| Price per GB | Lower | Higher |
| Performance | Slightly faster latency | Slightly higher latency |
| Best For | Cost-effective upgrades | Maximum capacity builds |
| Mixing Rule | Cannot mix with LRDIMM | Cannot mix with RDIMM |
Pro Tip: Never mix RDIMM and LRDIMM in the same server. The server will fail to POST. Pick one type and stick with it across all slots.
Most Popular HP Server Memory Part Numbers
DDR4 (Gen9, Gen10, Gen10 Plus)
| HP Part Number | Capacity | Speed | Type | Fits |
|---|---|---|---|---|
| 815100-B21 | 32GB | 2666MHz | RDIMM | Gen10 |
| 838083-B21 | 32GB | 2666MHz | RDIMM | Gen10 |
| 805351-B21 | 32GB | 2400MHz | RDIMM | Gen9 |
| 726719-B21 | 16GB | 2133MHz | RDIMM | Gen9 |
| 836220-B21 | 16GB | 2400MHz | RDIMM | Gen9 |
| 809083-091 | 32GB | 2400MHz | RDIMM | Gen9 |
| 815098-B21 | 16GB | 2666MHz | RDIMM | Gen10 |
| P00924-B21 | 32GB | 2933MHz | RDIMM | Gen10 |
| P00930-B21 | 64GB | 2933MHz | RDIMM | Gen10 |
| 809084-091 | 32GB | 2400MHz | LRDIMM | Gen9 |
DDR3 (Gen8)
| HP Part Number | Capacity | Speed | Type | Fits |
|---|---|---|---|---|
| 672631-B21 | 16GB | 1600MHz | RDIMM | Gen8 |
| 647901-B21 | 16GB | 1333MHz | RDIMM | Gen8 |
| 647883-B21 | 16GB | 1333MHz | RDIMM | Gen8 |
| 632204-001 | 16GB | 1333MHz | RDIMM | Gen8 |
| 708641-B21 | 16GB | 1866MHz | RDIMM | Gen8 |
| 647650-071 | 8GB | 1333MHz | RDIMM | Gen8 |
| 647897-B21 | 8GB | 1333MHz | RDIMM | Gen8 |
Memory Population Rules for HP ProLiant
HP servers are picky about DIMM slot population order. Installing DIMMs in the wrong slots causes performance degradation or boot failure.
Single CPU Configuration:
- Populate white slots first, then black slots
- Fill channel A, B, C evenly across the CPU
Dual CPU Configuration:
- Balance memory evenly between CPU 1 and CPU 2
- Populate in 1 DIMM per channel, then 2 per channel, then 3 per channel
- Asymmetric population works but reduces memory bandwidth
Speed Considerations:
- 1 DIMM per channel = runs at maximum rated speed
- 2 DIMMs per channel = may downclock by one speed bin
- 3 DIMMs per channel = typically downclocks by two speed bins
HP SmartMemory vs Third-Party Memory
HP SmartMemory modules include an EEPROM chip that HP iLO recognizes. If you install non-SmartMemory, iLO displays a warning but the memory functions normally.
How Much RAM Do You Need?
| Use Case | Recommended RAM | Typical Config |
|---|---|---|
| Basic file server | 32-64GB | 4x 16GB RDIMM |
| VMware ESXi (5-10 VMs) | 128-256GB | 8x 16GB or 4x 32GB |
| VMware ESXi (20+ VMs) | 256-512GB | 8x 32GB or 8x 64GB |
| SQL Server database | 128-384GB | Depends on DB size |
| Hyper-V / Proxmox | 128-256GB | 8x 16GB or 8x 32GB |
| Terminal Server / RDS | 64-128GB | 4x 16GB or 4x 32GB |
In-stock items ordered before 3pm ET ship the same day. Need help choosing the right memory for your ProLiant? Contact sales@prodisknetwork.com with your server model.