QNAP All-Flash NAS Memory Upgrades
ECC memory for QNAP all-flash NAS — the TS-h FU and FX rackmounts, the TDS-h2489FU, the QAI-h1290FX, the all-flash ES2486AFdc, and the DDR5 TS-h1077AFU, TS-h3077AFU and TS-h1277AFX — systems that run entirely on SSDs rather than spinning disks.
All-flash changes what the memory has to do. With no seek latency to hide behind, the bottleneck moves to the controller, and QuTS hero, the ZFS operating system on these units, uses RAM for its ARC read cache and its deduplication tables. On an all-flash unit, memory is what lets the flash perform.
The all-flash lineup and what each unit takes
| Model | Memory | Module sizes | Largest set we list |
|---|---|---|---|
| TS-h1090FU | DDR4-3200 ECC RDIMM | 16GB to 128GB | 8×128GB (1TB) |
| TS-h1290FX | DDR4-3200 ECC RDIMM | 16GB to 128GB | 8×128GB (1TB) |
| TS-h2490FU | DDR4-3200 ECC RDIMM | 16GB to 128GB | 8×128GB (1TB) |
| QAI-h1290FX | DDR4-3200 ECC RDIMM | 16GB to 128GB | 8×128GB (1TB) |
| TDS-h2489FU / R2 | DDR4-3200 ECC RDIMM | 16GB, 32GB | 8×32GB (256GB) |
| ES2486AFdc | DDR4-3200 ECC RDIMM, per controller | 16GB, 32GB, 64GB | 8×64GB (512GB) |
| TS-h1077AFU (non-ECC) | DDR5-5600 ECC or non-ECC UDIMM | 16GB, 32GB, 48GB | 4×48GB (192GB) |
| TS-h3077AFU (non-ECC) | DDR5 ECC (4800) or non-ECC (5600) UDIMM | 16GB, 32GB, 48GB | 4×48GB (192GB) |
| TS-h1277AFX | DDR5-5600 ECC UDIMM | 16GB, 32GB, 48GB | 4×48GB (192GB) |
Two module families: the DDR4 units are registered-memory (RDIMM) platforms with eight-module sets, and the DDR5 AFU and AFX units take full-size DDR5 UDIMM in four slots. The AFU units ship with ECC; for ZFS we recommend keeping ECC, and we also list non-ECC for buyers who need it. The dual-controller ES2486AFdc takes one identical set per controller — see the dual-controller page.
Sizing memory for an all-flash QuTS hero unit
On a spinning-disk NAS, RAM caches around disk latency. On all-flash the ARC serves metadata and hot blocks at memory speed, and the pool features that make QuTS hero worth running are the ones that consume it. Rules of thumb that hold up:
- Pool size: a common ZFS rule of thumb is about 1GB of RAM per TB of usable pool for an effective ARC.
- Inline deduplication: the dedup table lives in RAM and needs far more than plain storage. If the unit will run dedup, size for it up front or run compression without dedup.
- Compression: light on memory; it does not change the sizing much.
- Block storage: busy iSCSI and high-speed network targets hold buffer memory per session; add headroom for a block-storage role.
- Virtualization and containers: whatever the guests need, on top.
The common failure looks like slow SSDs: a large flash pool with dedup on, running at the base memory configuration. Bringing memory up is what fixes it.
Population rules on these platforms
- Use the module type the unit takes. RDIMM on the DDR4 FU, FX, TDS-h, QAI and ES units; UDIMM on the DDR5 AFU and AFX units. They are not interchangeable.
- Fill channels with identical modules. The EPYC-based FU and FX units run fastest with every memory channel populated, which is why our sets go to eight modules; a four-module upgrade leaves channels idle.
- Balance both processors on the dual-processor TDS-h2489FU, so neither CPU is left reaching across for memory.
- Match capacity, speed and rank. Mixed speeds run at the slowest module. Identical modules across the system is the safe configuration.
- Do not mix ECC and non-ECC on the DDR5 AFU units; use one type throughout.
Reading QNAP's part numbers
QNAP's codes give the capacity, generation, ECC marking, form factor and speed: RAM-16GDR5ECK0-UD-5600 is a 16GB DDR5-5600 ECC UDIMM. On registered parts the EC is often left out — RAM-32GDR4K0-RD-3200 is a 32GB DDR4-3200 RDIMM — but every RDIMM is ECC, so read the -RD suffix. Match a module by its QNAP code in the QNAP NAS Memory Cross-Reference.
How to check what is installed
- QuTS hero → Control Panel → System → System Status shows the installed memory; on the ES units, QES shows it per controller.
- QNAP's hardware specification for the model lists the slot count, the documented maximum and the QNAP RAM part numbers.
- The module label shows the capacity, speed, rank and the ECC / registered markings.
Ordering for deployments
All-flash QNAP units are bought in pairs and racks more often than singly. Researched, matched, and compatibility-tested by NEMIX RAM, a US-based server memory specialist since 1993, and backed by a lifetime warranty. NEMIX RAM is a registered federal supplier (UEI GV8MMYNDJ5J1, CAGE 59AB2) and accepts purchase orders with net terms for business, government and education buyers. Send the models, unit count and target capacity per unit to our sales team, or request a quote, and we return one quote with a matched set per unit. Volume and reseller pricing is available on request.
Frequently asked
Can I add four modules to my TS-h1090FU instead of eight? It will run, with fewer channels in use, and you will see it under load. If the budget allows only four now, buy four of the same module you will finish the set with.
Can I use an ECC UDIMM in a TS-h1290FX? No. The FX is a registered platform and takes RDIMM only; UDIMM and RDIMM are not interchangeable.
Do I need an SSD cache on an all-flash unit? Generally no — the pool is already flash. Memory is where the cache belongs on these units.
Where are the other QNAP units? Every QNAP model we cover is in the QNAP memory by model collection, and the QNAP NAS memory guide explains which platform takes which module.
See also: QNAP Dual-Controller NAS Memory · QNAP Enterprise NAS Memory · QNAP NAS Memory Cross-Reference
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