NAS Guides · Published 2026-10-21
NVMe SSD in a NAS: Cache, Storage Pool, and Network Shares
Direct answer up front, then the trade-offs that matter. This page covers nvme ssd and answers: What is a NAS and do I need one?.
By Konpin · Founder / Lead Analyst
Beat: Private-cloud economics · How we review
Quick Answer
An NVMe drive inside a NAS does one of two jobs: cache, or a storage pool. Which one you get is decided by the NAS model, not by the drive. Synology supports M.2 NVMe storage pools only on listed models running DSM 7.2 or later, and only with its own M.2 SSDs; on everything else the slots are cache-only. After the volume exists, you share it out — SMB for Windows and macOS, NFS for Linux and virtual machines, WebDAV for clients outside the LAN.
Key Takeaways
- Endurance separates the two drives people compare most. WD Red SN700 1 TB is rated 2,000 TBW; Samsung 990 PRO 1 TB is rated 600 TBW (vendor spec pages, checked 2026-10-21).
- Peak sequential speed is not the bottleneck. A 2.5GbE link carries 2.5 Gbit/s, which is 312 MB/s before protocol overhead.
- NAND Flash contract prices are forecast to rise 15–20% quarter over quarter in 4Q26 (TrendForce, 30 September 2026), so sizing correctly now costs less than adding capacity in January.
- Synology's M.2 storage-pool list covers the 25-series, including DS925+, DS1525+, DS425+ and DS725+, on DSM 7.2 and later (Synology Knowledge Center, accessed 2026-10-21).
- Windows reaches the volume over SMB on ports 137–139 and 445, Linux over NFS, and remote clients over WebDAV on the default HTTPS port 5006.
What Changed
Price moved first, and it moved against buyers. TrendForce's 30 September 2026 note puts NAND Flash contract prices at +15–20% for the fourth quarter, with enterprise SSDs the only memory category whose increases are speeding up rather than slowing. Enterprise SSD bit demand is projected to grow more than 80% year over year in 2026, driven by CSP inference build-outs.
Cheaper is relative.
A second read on the same quarter came from Morgan Stanley, reported by TechNews on 17 October 2026: NAND pricing revised from +0–5% to +15–20%, enterprise SSDs at +23–28%, and consumer NAND inventory still accumulating while suppliers lean on bundle deals to clear it.
Read those two together and the retail picture makes sense. Deal posts keep appearing — PC Guide flagged a low price on a 1 TB Samsung 990, XDA ran the argument that paying more for NVMe still beats SATA in 2026 — while contract prices climb underneath.
Discounts on client drives are a channel clearing problem. They are not a signal that flash is getting cheaper.
Who Is It For
Three groups get real value from flash inside a NAS. Home-lab operators running virtual machines and containers on a 2.5GbE box, where random reads decide how fast a VM boots. Photographers and video editors who keep active projects on the array and want thumbnails and previews to appear without a spinning-disk pause. Small offices with several people hitting the same shared folder at once.
It is a poor fit for other people. If your NAS sits on 1GbE, a Gen4 drive changes nothing you can feel. If the library is 8 TB of films, flash is the wrong tier entirely — the capacity math does not work at any price. And if the box is a single-user backup target that writes once a night, cache is a purchase looking for a problem.
The distinction matters because vendors sell "NVMe support" as a headline feature. Support for a slot is not support for a storage pool.
Slots are cheap to add. Pool support is the expensive part. Editors weighing a first array will find the model-by-model trade-offs in our NAS picks for content creators.
Key Specifications
Capacity and bays
The drive is 1 TB in both cases here, M.2 2280. On the NAS side, a DS925+ carries four SATA bays and two M.2 slots (our spec ledger, checked 2026-10-02), and a storage pool cannot mix drive types — SATA and NVMe stay in separate pools (Synology DSM 7 Help, accessed 2026-10-21). Two M.2 slots means one pool at RAID 1, or two pools at RAID 0 with no redundancy.
Two slots. One mirror.
Connectivity
WD Red SN700 1 TB runs PCIe Gen3 x4 at 3,430 MB/s read and 3,000 MB/s write. Samsung 990 PRO 1 TB runs PCIe Gen4 x4 with NVMe 2.0 at 7,450 MB/s read and 6,900 MB/s write (both vendor spec pages, checked 2026-10-21).
Put either behind a 2.5GbE port and the ceiling is 312 MB/s. The Gen4 advantage is real on a desktop. In a NAS it waits for 10GbE.
Software stack
DSM 7.2 or later is the floor for M.2 storage pools. Storage Manager handles pool creation, and the file services — SMB, NFS, WebDAV — are separate switches under Control Panel. None of them are on by default.
What Is New
Official M.2 storage-pool support is the change worth knowing about. It arrived with DSM 7.2, and Synology publishes the model list rather than leaving it to trial and error: DS1825+, DS1525+, DS925+, DS725+, DS425+ and their neo variants on the 25-series, with 23-series and 21-series units also listed (Synology Knowledge Center, accessed 2026-10-21).
Two conditions come attached. The first is drive identity — the knowledge base states that only Synology M.2 SSDs compatible with your model should be used for a storage pool, which is a compatibility list, not a suggestion. The second is boot: DSM cannot be installed on an M.2 SSD, so at least one non-M.2 drive has to stay in the system.
What has not changed is the honest framing. Flash in a NAS buys latency and quiet, not throughput. Anyone buying for throughput is buying for the switch they have not installed yet.
Buy the switch later, if at all.
How It Compares
The table below comes straight from our spec and price ledger, one row per official spec field. No cell is filled in from memory.
WDS100T1R0C vs a client-class drive (spec and price, generated from the ledger)
| Field | WD Red SN700 1 TB NVMe SSD (WDS100T1R0C) | Samsung 990 PRO 1 TB (MZ-V9P1T0BW) |
|---|---|---|
| Price (tracked) | Walmart $145.38 (2026-10-21) | — |
| Capacity | 1 TB | 1 TB |
| MTBF | — | 1500000 hours |
| Form factor | M.2 2280 S3-M | M.2 2280 |
| Warranty | 5 years | 5 years |
| Interface | PCIe Gen3 x4 (NVMe) | PCIe Gen4 x4, NVMe 2.0 |
| Sequential read | 3430 MB/s | 7450 MB/s |
| Sequential write | 3000 MB/s | 6900 MB/s |
| Endurance | 2000 TBW | 600 TBW |
_Sources: Samsung 990 PRO NVMe M.2 SSD 1TB (MZ-V9P1T0BW) — official specification table, Samsung New Zealand · WD Red SN700 NVMe SSD — official specifications (Sandisk/Western Digital product page), 1TB column_
_— = no verified reading for that field in the ledger (never substitute a sibling product's number). Struck-through figures = stale readings only._
The interesting column is Endurance. Two thousand TBW against six hundred is a 3.3× difference in rated write life, and it is the number that separates a drive sold for NAS duty from a drive sold for a desktop. Samsung's own spec sheet lists Application as Client PCs and Game Consoles. There is no NAS row. That is not a defect — it is a declaration of the workload the drive was validated against.
Warranty terms read the same, five years on both, but Samsung's is five years or 600 TBW, whichever comes first (Samsung, checked 2026-10-21). A cache drive that absorbs every write to a busy array will reach a TBW ceiling before a calendar ceiling.
Who Should Consider It
Buy the cache first. It is the cheaper experiment, it reuses the slots you already have, and it tells you whether your workloads are actually random-read bound without committing the array to flash.
Worth it if you run VMs or containers off the NAS, edit photos with the catalogue on a share, or support more than three concurrent users on 2.5GbE. Worth it if the noise of four spinning disks in a living room is a genuine annoyance.
Skip it if the array is mainly cold archive, if the network is still 1GbE, or if 4 TB of active video is the requirement — that is a hard-disk job. Skip it if your model is not on Synology's list, because cache is then the only option and the pool argument disappears.
The trade-off is straightforward: flash buys latency per dollar, spinning rust buys capacity per dollar, and no single array does both well. If the real question is whether to keep renting cloud storage at all, our public cloud versus private NAS comparison works the same numbers over five years.
What Existing Users Should Know
Upgrades are where this gets awkward. M.2 is not hot-swappable, and Synology's guidance is to shut the unit down and disconnect cables before inserting or removing a drive. Maintenance that involves the M.2 slots means downtime, not a swap during business hours.
Plan the downtime.
High Availability does not support pools built on M.2 SSDs, per the same knowledge base. If uptime is the reason you bought a Plus-series unit, that constraint may decide the question for you.
Creating a pool wipes the drives — the DSM help page is explicit that existing data on the selected drives is deleted during creation. Back up before you start, and confirm drive health in Storage Manager first.
One item we could not verify: how firmly DSM enforces the Synology-only M.2 list on every model and firmware combination. Our reading of the documentation says non-listed drives are refused for pool creation, but behaviour across firmware revisions is not something we can confirm from published sources. If a drive is on the compatibility list, that question never comes up.
Real-World Scenario: SMB / WebDAV / NFS Cross-Protocol Mounting
What this changes for the use case
A fast volume that only one machine can reach is a local disk with extra steps. The scenario that justifies the purchase is a mixed fleet: a Windows workstation for editing, a Mac for colour work, a Linux box or Proxmox host running containers, and a laptop that travels. Each of those wants a different protocol, and DSM runs all three at once from the same volume.
SMB is the default for Windows and macOS. NFS suits Linux clients and hypervisors, where POSIX permissions matter more than user logins. WebDAV is the one that survives leaving the building, because it rides HTTPS.
One volume, three doors.
Hardware and software requirements
SMB lives under Control Panel > File Services > SMB, and Windows needs ports 137–139 and 445 open on both ends (Synology Knowledge Center, accessed 2026-10-21). NFS lives under File Services > NFS; permissions are set per shared folder under Edit > NFS Permissions, and the "allow connections from non-privileged ports" box has to be ticked or mounts fail silently (Synology Knowledge Center, accessed 2026-10-21). WebDAV is a package — install WebDAV Server from Package Center, enable HTTP and HTTPS, and note the default HTTPS port 5006; mapping it as a Windows drive also requires importing a valid certificate first.
On the hardware side, one wired 2.5GbE link and a switch that does not negotiate down to 1GbE. Nothing exotic.
Limits, caveats, and who should skip it
NFS has no user authentication by default — access is granted by host or IP — so it belongs on a LAN, never on a forwarded port. SMB3 transport encryption works, and it costs NAS CPU on every transfer. WebDAV exposed to the internet without a real certificate trains users to click through warnings, which defeats the point.
Skip the whole protocol exercise if one Windows machine is the only client. SMB alone covers it, and the extra services only widen the attack surface.
Frequently Asked Questions
Can I put any NVMe SSD in a Synology NAS?
Not for a storage pool. Synology states that only compatible Synology M.2 SSDs should be used to build pools, and the model list is published separately from the drive list. Cache use is the fallback for drives and models outside those lists.
Is an NVMe cache or a storage pool the better buy?
Cache is the cheaper test and helps random-read workloads on a hard-disk array. A pool gives you a real volume with predictable latency. If your model supports pools and your active data fits in 1–2 TB, the pool is the more useful purchase.
Will a Gen4 drive make my NAS faster?
Only past the network. A 2.5GbE link tops out at 312 MB/s before overhead, so a 7,450 MB/s drive and a 3,430 MB/s drive feel identical over that link. Gen4 pays off on 10GbE or in a desktop.
Do I need 10GbE to notice the difference?
For sequential transfers, yes. For random reads — VM boots, thumbnail generation, database files — no. Latency improves over 2.5GbE; throughput does not.
Sources
- TrendForce, "AI Server Demand Sustains Memory Contract Price Increases in 4Q26, While Consumer-Side Pressure Persists," 30 September 2026 — https://www.trendforce.com/presscenter/news/20260930-13258.html (accessed 2026-10-21)
- TechNews, report on Morgan Stanley memory supply-chain outlook (4Q26 NAND revised to +15–20%, enterprise SSD +23–28%), 17 October 2026 — https://technews.tw/2026/10/17/morgan-stanley-memory-and-ai-supply-chain-outlook/ (accessed 2026-10-21)
- Synology Knowledge Center, "Which Synology NAS models support M.2 SSD storage pools?" — https://kb.synology.com/DSM/tutorial/Which_models_support_M_2_SSD_storage_pool (accessed 2026-10-21)
- Synology, DSM 7 Help, "Create a Storage Pool" — https://www.synology.com/en-global/knowledgebase/DSM/help/DSM/StorageManager/storage_pool_create_storage_pool?version=7 (accessed 2026-10-21)
- Synology Knowledge Center, "How do I map a network drive using Synology Assistant?" (SMB service location and ports) — https://www.synology.com/en-global/knowledgebase/DSM/tutorial/File_Sharing/How_to_map_network_drives_from_your_Synology_NAS (accessed 2026-10-21)
- Synology Knowledge Center, "I cannot mount shared folders via NFS, what should I do?" — https://kb.synology.com/DSM/tutorial/I_cannot_mount_shared_folders_via_NFS_what_should_I_do (accessed 2026-10-21)
- Synology Knowledge Center, "How do I access files on Synology NAS with WebDAV?" — https://www.synology.com/en-global/knowledgebase/DSM/tutorial/File_Sharing/How_to_access_files_on_Synology_NAS_with_WebDAV (accessed 2026-10-21)
- Sandisk (Western Digital), WD Red SN700 NVMe SSD official specifications, 1 TB — https://www.sandisk.com/products/ssd/internal-ssd/wd-red-sn700-nvme-ssd?sku=WDS100T1R0C-68BDK0 (accessed 2026-10-21)
- Samsung, 990 PRO NVMe M.2 SSD 1TB (MZ-V9P1T0BW) official specification table — https://www.samsung.com/nz/memory-storage/nvme-ssd/990-pro-1tb-nvme-pcie-gen-4-mz-v9p1t0bw/ (accessed 2026-10-21)
- Walmart listing, Western Digital 1 TB WD Red SN700 NVMe SSD (WDS100T1R0C-68BDK0), $145.38, marked out of stock — https://www.walmart.com/ip/906676280 (accessed 2026-10-21)
Run your own 5-year cost comparison with the on-site calculator
Every figure above is attributed in the Sources list — put your own drive count and subscription tiers into the calculator to see where you land.
Open the cost calculator →Related reading
Was this article helpful?
One tap, no account and no comment box. It tells us which guides are actually worth updating.
How many drive bays is your NAS?
This is how we decide which setups to cover next.
Thanks.
Need help with a specific setup?
Storage choices depend on your drives, your budget and how many people share the box. Tell us what you are building and we will point you at a configuration that fits — no obligation, no sales script.
Affiliate Disclosure: SecureNAS Hub may earn a commission from qualifying purchases made through links on this page, at no extra cost to you. Facts and figures are attributed in the Sources list; nothing on this page is a fabricated test result. See our full disclosure. Product images are either supplied by the manufacturer or clearly labelled as illustrative renders; each one is captioned accordingly. Last reviewed 2026-10-21.