Best 4-Bay NAS 2026 — The Sweet-Spot Buying Guide
Checked October 17, 2026
Our current picks for this
These passed our buyer-review check (4+ stars, real review volume, and no reliability or durability complaints outnumbering praise) and link to the exact Amazon listing. Stock is re-checked daily.
Four bays is the home-NAS sweet spot: in RAID 5 or SHR you get roughly (n-1) drives of usable space (4×8TB ≈ 24TB usable), single-drive fault tolerance with an escape hatch to two-drive redundancy (RAID 6 / SHR-2), and one-at-a-time capacity upgrades. The pick splits on one fork: for buyers who want an appliance it's the Synology DS425+ (DSM, Plex transcoding, a 2.5GbE port, two M.2 slots, but a 6GB RAM ceiling); for power users it's the QNAP TS-464 (dual 2.5GbE, 16GB RAM ceiling, a PCIe slot for 10GbE). The TerraMaster F4-424 is the raw hardware-value pick, the Asustor AS5404T the NVMe-flexibility pick (four M.2 slots), and the UGREEN DXP4800 the newcomer-value pick. Whatever you buy: CMR drives only, and RAID is not a backup.
The one thing to know: RAID is not a backup. RAID (except RAID 0) protects against DRIVE failure — if one disk dies, the array keeps running while you replace it. It does nothing against the things that actually destroy data: accidental deletion, ransomware, file corruption, a failed controller, theft, fire, or a power surge that takes the whole box. All of those hit the live array and every mirror of it at once. RAID is about uptime and availability; a backup is a separate, ideally offline or off-site copy you can restore from. You need both, and 'I have RAID' is the single most common — and most dangerous — misconception in home storage.
The best 4-bay NAS, ranked
Research-based picks (how we evaluate) built from manufacturer specifications and storage engineering — no prices, no star ratings, qualitative tier bands only, and an honest drawback on every box. Every enclosure ships empty; the drives row at the end covers the other half of the purchase.
Synology DiskStation DS425+
Tier band: Mid / upper-mid tier (enclosure only)
4 bays · Intel Celeron J4125 quad-core (2.0GHz, 2.7GHz turbo) · 2GB DDR4 non-ECC (one slot, expandable to 6GB) · 1× 2.5GbE + 1× 1GbE · 2× M.2 2280 NVMe (SSD cache) · DSM · hardware H.264/H.265 transcoding
Four bays of DSM with an Intel CPU that hardware-transcodes for Plex, a 2.5GbE port and two M.2 slots for SSD cache: the polished Synology experience at four-drive capacity.
Best for: Homes that want DSM's polish, four bays of capacity and a Plex-capable CPU, without homelab tinkering
Our verdict: The 4-bay Synology most homes should buy: DSM's polish, room for four drives and a CPU that can transcode for Plex. Power users who need ECC or a 32GB RAM ceiling should look at the DS925+ or the QNAP TS-464 instead.
Check price on AmazonNot deciding today? Add it to your cart over there — Amazon keeps it saved (and flags any price change) until you're ready.
Watch out: The trade is headroom. The J4125 is a modest 2020-era chip, RAM tops out at 6GB with no ECC, and there is no 10GbE upgrade path, so it is not a heavy Docker or VM host. Synology's ECC 4-bay is the DS925+ (AMD Ryzen V1500B, 4GB ECC to 32GB, two 2.5GbE), which has no integrated GPU and so cannot hardware transcode. On DSM 7.3 hard drives not on Synology's list can be used for new storage pools, but unlisted M.2 NVMe SSDs cannot be used for a pool or cache.
QNAP TS-464
Tier band: Mid tier (enclosure only)
4 bays · Intel Celeron N5095 quad-core · 4GB DDR4 (expandable to 16GB) · 2× 2.5GbE · 2× M.2 PCIe Gen3 NVMe · PCIe Gen3 expansion slot · HDMI 4K · QTS/QuTS hero · hardware transcoding
The flexible 4-bay tinkerer's box: dual 2.5GbE, two NVMe slots, and a rare PCIe slot you can populate with a 10GbE card or extra M.2 carrier as your needs grow.
Best for: Power users and self-hosters who want an upgrade path (10GbE via PCIe) on an affordable 4-bay
Our verdict: The best all-round 4-bay value for a power user: 2.5GbE and NVMe today, and a PCIe slot that means 10GbE tomorrow. It's the box that grows with your homelab instead of capping it.
Check price on AmazonNot deciding today? Add it to your cart over there — Amazon keeps it saved (and flags any price change) until you're ready.
Watch out: Same QNAP security caveat as the TS-264 — never expose it directly to the internet, and patch it. The 4GB base RAM is modest for heavy container/VM use, so budget for a RAM upgrade if you plan to run many apps.
TerraMaster F4-424
Tier band: Value / mid tier (enclosure only)
4 bays · Intel N95 quad-core · 8GB DDR5 (expandable to 32GB) · 2× 2.5GbE · TOS 6 operating system · also supports third-party OS (TrueNAS / Unraid) · hardware transcoding
The most raw hardware per dollar here — a current N95 CPU, 8GB of DDR5 expandable to 32GB, and dual 2.5GbE — and TerraMaster openly documents installing TrueNAS or Unraid if you outgrow its own OS.
Best for: Budget-conscious buyers who value hardware specs and the option to run a third-party NAS OS
Our verdict: Flat-out the most hardware for the money in this list — and because TerraMaster openly supports TrueNAS and Unraid, it's our favorite budget 4-bay to buy as a long-term platform, not just an appliance.
Check price on AmazonNot deciding today? Add it to your cart over there — Amazon keeps it saved (and flags any price change) until you're ready.
Watch out: TerraMaster's own TOS software is less mature and less polished than Synology DSM, with a smaller app catalog, and the brand has had past security-hardening criticism — keep it off the open internet. Its main appeal for many buyers is as capable hardware to run TrueNAS/Unraid on, not the bundled OS.
Asustor AS5404T (Nimbustor 4 Gen2)
Tier band: Mid tier (enclosure only)
4 bays · Intel Celeron N5105 quad-core · 4GB DDR4 (expandable to 16GB) · 2× 2.5GbE · four M.2 NVMe slots (usable as storage or cache) · HDMI · ADM operating system · hardware transcoding
Its standout is four M.2 NVMe slots — enough to build a genuine all-flash NVMe pool or generous cache alongside the four HDD bays, which is unusual at this size and price.
Best for: Users who want to mix hard-drive capacity with a fast NVMe pool, or maximize flash flexibility
Our verdict: Nothing else at this size gives you four NVMe slots next to four drive bays. If a fast flash pool alongside big spinning-disk capacity is your build, this is the pick.
Check price on AmazonNot deciding today? Add it to your cart over there — Amazon keeps it saved (and flags any price change) until you're ready.
Watch out: Asustor's ADM operating system and app ecosystem are smaller and less widely documented than Synology's or QNAP's, so you'll lean more on community guides. Base RAM is only 4GB, and the M.2 slots share PCIe lanes — check current documentation for full-population performance behavior.
UGREEN NASync DXP4800
Tier band: Mid tier (enclosure only)
4 bays (+2 M.2) · Intel N100 quad-core · 8GB DDR5 (expandable to 16GB) · 2× 2.5GbE · 2× M.2 NVMe · HDMI · UGOS Pro · also runs third-party OS · hardware transcoding
A 4-bay take on the same value formula — N100, DDR5, dual 2.5GbE, plus two NVMe slots and extra bays for a capacity-plus-flash build, at an aggressive price for the hardware.
Best for: Buyers who want a modern, well-priced 4-bay and are comfortable with a newer software ecosystem (or plan to run TrueNAS)
Our verdict: The same value formula with room to grow: four bays, dual 2.5GbE, and NVMe at a price the legacy brands don't match. If you want a modern 4-bay and aren't wedded to DSM, buy this.
Check price on AmazonNot deciding today? Add it to your cart over there — Amazon keeps it saved (and flags any price change) until you're ready.
Watch out: Same newness caveat as the DXP2800: UGOS Pro is young and its long-term support/security history is still being written, so weigh that against the hardware value — and consider TrueNAS if you want a proven, community-supported OS on it.
The Drives NAS Hard Drives — WD Red Plus / Seagate IronWolf (CMR)
Tier band: Priced per drive by capacity (bought separately from the enclosure)
3.5" NAS-rated hard drives · CMR (conventional) recording — NOT SMR · rated for 24×7 operation and multi-drive vibration · NASware / AgileArray firmware · common home capacities run through the mid-double-digit-TB range
Every NAS above ships as an empty enclosure — the drives are the other half of the purchase. NAS-rated CMR drives (WD Red Plus, Seagate IronWolf) are built for 24×7 duty, vibration in multi-bay chassis, and RAID rebuilds, which desktop drives are not.
Best for: Anyone buying a NAS enclosure who needs reliable, rebuild-safe drives to populate it
Our verdict: Whichever enclosure you choose, NAS-rated CMR drives are the right call — WD Red Plus and Seagate IronWolf are both proven lines built for 24×7 array duty, and either one belongs in your cart alongside the enclosure.
Check price on AmazonNot deciding today? Add it to your cart over there — Amazon keeps it saved (and flags any price change) until you're ready.
Watch out: Avoid SMR (shingled) drives in a NAS RAID array — SMR's slow re-write behavior can make RAID rebuilds crawl or fail. The plain WD Red (non-Plus) and many cheap desktop/external-shucked drives are SMR; confirm CMR on the spec sheet. Buy from a source with a clear return path in case of early failure, and always run a NAS with a real backup — RAID is not a backup.
Complete your setup
NAS-ready hard drives (CMR)
Every enclosure above ships empty. Seagate IronWolf and WD Red Plus are the two proven NAS-rated CMR lines — confirm CMR on the spec sheet before you buy.
Shop on Amazon →UPS battery backup
A NAS hates dirty shutdowns — a power cut mid-write can corrupt an array. A UPS in the APC Back-UPS line lets the NAS shut down cleanly when the lights go out.
Shop on Amazon →Cat6 Ethernet cable
2.5GbE is only as good as the cable. Cat6 handles 2.5GbE (and 10GbE at short runs) — a cheap fix for a NAS still hanging off an old patch lead.
Shop on Amazon →Why is a 4-bay NAS the sweet spot?
The 4-bay case rests on arithmetic, not marketing. RAID redundancy has a fixed cost in drives, and four bays is where that cost stops hurting:
- Usable capacity: (n-1) instead of (n/2). A 2-bay mirror gives up half its raw space to redundancy. A 4-bay in RAID 5 or single-redundancy SHR gives up only one drive: 4×8TB ≈ 24TB usable, 4×12TB ≈ 36TB — three times the usable space of a 2-bay mirror built from the same drives, for one extra drive's worth of redundancy overhead.
- One-at-a-time upgrades. With four bays you can grow capacity by replacing drives individually as budget allows (especially flexible under SHR, which uses mixed sizes efficiently — SHR vs classic RAID), or start with two or three drives and add more later. A full 2-bay has no such path except replacing both drives.
- Single-drive tolerance with an escape hatch. RAID 5/SHR survives one drive failure. If the array grows large and a second failure during a rebuild starts to worry you, four bays lets you step up to RAID 6 / SHR-2 (two-drive redundancy) — an option a 2-bay simply doesn't have. More on sizing in how many bays do you need.
Beyond four bays, diminishing returns set in for most homes: 6- and 8-bay boxes cost more, draw more power, and mostly serve buyers who already know they need them.
Appliance or headroom? The fork that decides your 4-bay pick
All five boxes here can hardware-transcode for Plex or Jellyfin, so the honest either/or is software polish against hardware headroom:
- Appliance buyers want DSM. The Synology DS425+ runs the most polished NAS software there is, its Celeron J4125 transcodes in hardware, and it adds a 2.5GbE port and two M.2 slots for SSD cache. The price of that polish is headroom: 2GB of RAM with a 6GB ceiling, no ECC, one 2.5GbE port rather than two, and no 10GbE path.
- Power users want headroom. The QNAP TS-464, TerraMaster F4-424, Asustor AS5404T and UGREEN DXP4800 all ship dual 2.5GbE and take 16GB of RAM or more; the TS-464 adds a PCIe slot for a 10GbE card, and the F4-424 reaches 32GB. Their software is less polished than DSM.
- ECC buyers have one Synology option. The DS925+ (AMD Ryzen V1500B, 4GB ECC to 32GB, two 2.5GbE) is Synology's ECC 4-bay, but the Ryzen has no integrated GPU, so it is a poor transcoding box: plan on direct play or a separate transcoding machine.
Be honest about which buyer you are. If you want storage, photos and Plex working without tinkering, buy the DS425+. If you plan to run many containers or VMs, buy the RAM ceiling (Docker/VM capability by CPU class). ECC is nice, not mandatory: a tested backup protects your data far more.
4-bay spec comparison — the specs that matter
From our master spec data (Synology specs read on synology.com on 8 October 2026). Note the RAM row: the DS425+ has the lowest ceiling here, which is the price of DSM at this size.
| Feature | Synology DS425+ | QNAP TS-464 | TerraMaster F4-424 | Asustor AS5404T | UGREEN DXP4800 |
|---|---|---|---|---|---|
| CPU class | Celeron J4125 (x86) | Celeron N5095 (x86) | Intel N95 (x86) | Celeron N5105 (x86) | Intel N100 (x86) |
| RAM base → max | 2GB → 6GB | 4GB → 16GB | 8GB → 32GB | 4GB → 16GB | 8GB → 16GB |
| Networking | 1× 2.5GbE + 1× 1GbE | 2× 2.5GbE | 2× 2.5GbE | 2× 2.5GbE | 2× 2.5GbE |
| NVMe slots | 2× M.2 | 2× M.2 (+PCIe) | Varies by rev. | 4× M.2 | 2× M.2 |
| ECC | No | No | No | No | No |
| OS | DSM | QTS / QuTS | TOS / TrueNAS | ADM | UGOS / TrueNAS |
| iGPU / transcoding | Yes (Intel iGPU, hardware transcoding) | Yes (Intel iGPU, hardware transcoding) | Yes (Intel iGPU, hardware transcoding) | Yes (Intel iGPU, hardware transcoding) | Yes (Intel iGPU, hardware transcoding) |
Don't forget the drives: CMR only, and a rebuild is the stress test
NAS-rated drives use CMR (conventional magnetic recording); many cheap desktop and external drives use SMR (shingled), which overlaps tracks to pack in more capacity but must rewrite whole zones on write, making sustained and random writes slow. In a NAS this matters most during a RAID rebuild: an SMR drive can slow a rebuild to a crawl or cause it to drop out of the array, risking a second failure before it finishes. Use CMR NAS drives (WD Red Plus, Seagate IronWolf) in an array; the plain WD Red was infamously SMR. Always confirm CMR on the spec sheet.
This matters more on a 4-bay than a 2-bay: a four-drive RAID 5 rebuild reads every surviving drive end-to-end while writing the replacement, and an SMR drive in that array is exactly how rebuilds crawl or fail. Stick to WD Red Plus or Seagate IronWolf class CMR drives and confirm CMR on the spec sheet — full CMR vs SMR explainer.
Frequently Asked Questions
If you can afford the enclosure and the extra drives, usually yes. In RAID 5 or SHR a 4-bay gives you roughly (n-1) drives of usable space — with 4×8TB that's about 24TB usable versus 8TB from a 2-bay mirror using comparable drives — plus the option of two-drive redundancy (RAID 6 / SHR-2) and one-at-a-time capacity upgrades. A 2-bay mirror 'costs' half its raw space to redundancy; a 4-bay RAID 5 costs only a quarter. If your needs are just photos and backups, a 2-bay is still plenty.
One with an Intel integrated GPU, which all five picks here have: the Synology DS425+ (Celeron J4125), QNAP TS-464, TerraMaster F4-424, Asustor AS5404T and UGREEN DXP4800 all hardware-transcode. The one to avoid for Plex is Synology's ECC 4-bay, the DS925+: its AMD Ryzen V1500B has no integrated GPU, so plan on direct play or a separate transcoding box if you buy it.
No — ECC is nice, not mandatory. The 'ZFS requires ECC or it eats your data' claim is a myth; non-ECC boxes protect data for millions of users, and a tested backup protects your data far more than ECC does. None of these five has ECC; in Synology's 4-bay range it is the DS925+ (4GB ECC, expandable to 32GB) that offers it, at the cost of hardware transcoding. Treat ECC as a bonus, not a checkbox.
In RAID 5 or single-redundancy SHR, roughly the total of all drives minus one: 4×8TB ≈ 24TB usable, 4×12TB ≈ 36TB usable. RAID 6 / SHR-2 (two-drive redundancy) subtracts two drives: 4×8TB ≈ 16TB usable. RAID 10 halves raw capacity. These are approximations before filesystem overhead — and remember RAID redundancy is availability, not a backup.
NAS-rated CMR drives — WD Red Plus or Seagate IronWolf. Avoid SMR (shingled) drives in any RAID array: SMR's slow rewrite behavior can make a rebuild crawl or drop the drive from the array, and a 4-drive rebuild is exactly when you can't afford that. The plain WD Red (non-Plus) and many cheap desktop or shucked drives are SMR — confirm CMR on the spec sheet. Every enclosure here ships empty; the drives are the other half of the purchase.
It protects against one drive failing while the array stays online — nothing more. It does nothing against accidental deletion, ransomware, corruption, theft, or fire, which hit the live array all at once. On larger arrays a second drive can fail during the stressful rebuild, which is why some owners choose RAID 6 / SHR-2. Either way, RAID is not a backup: keep a separate 3-2-1 backup (3 copies, 2 media types, 1 off-site) and test a restore.
How we work
We're a research-based site: we analyze manufacturer specifications, storage and filesystem engineering, and aggregated owner-feedback themes rather than lab-testing every enclosure. We explain tradeoffs plainly, always name a downside, and report measurable specs — never a guarantee about data safety. RAID is not a backup, drives fail, and only a tested 3-2-1 backup protects your data. Read our full methodology →