Best 4-Bay NAS of 2026

Synology's hardware has never been the reason to buy Synology, and the DS425+ is the clearest example in this set. The listed 278 MB/s is modest beside the 10-gigabit picks, and there's nothing exotic inside the chassis. What you pay for is DSM: a backup suite that images PCs and Microsoft 365 mailboxes, snapshot protection that turns ransomware into a restore job, surveillance for up to 30 cameras, and photo and file apps that people who aren't IT staff can use. The warranty runs three years, one of the longer ones here.

We came away thinking of it as the low-drama choice. It's rated for more than ten simultaneous users, and the platform's real advantage is predictability — the same interface, backup jobs, and permissions in year three as in week one. Set up laptop backups and phone photo sync once and the DS425+ stops asking for attention, which is the entire reason to pay for DSM instead of learning something new.

The catch is drive choice. Synology publishes an approved-drive list for its current models, and drives that don't appear on it can be refused or flagged, so match the exact model number before you order four disks. Sort that out first and the rest of the setup is uneventful.

Two M.2 slots sit inside this one, and they're the reason it earns a place. On the TS-464 they can act as a cache for the four spinning disks or become a separate SSD pool where the files you open every day actually live. It's the kind of flexibility that pays off later: start with four hard drives, add speed without touching the array.

The rest of the spec sheet is sensible rather than flashy — an Intel quad-core that bursts to 2.9GHz, 8GB of DDR4 you can add to, dual 2.5GbE ports, and USB 3.2 Gen 2 for pulling files off external drives at up to 10Gb/s. QTS guided us through shares and apps without much hunting, and the metal chassis with hot-swap trays feels sturdier than the price suggests.

Here's the honest arithmetic. Two 2.5GbE ports only help if your switch and the machine you're copying from can match them; on a plain gigabit network all that headroom disappears. SSD caching also does far more for repeated reads — photo thumbnails, Plex artwork — than for one giant file copy. The value rests on using those slots, not on owning them, and that's the test to apply before you buy.

Four bays, the same DSM software as the DS425+, and the lowest price of any Synology here. The pitch is straightforward: snapshots that undo a ransomware encryption, backups to a second destination, shared folders that replace a subscription, and surveillance for up to 30 cameras with licenses bought separately. The chassis is metal and the warranty runs two years.

Where it gives ground is headroom, and the setup. Nothing underneath is exotic, and a few steps the newer UGREEN boxes walk you through are choices you make yourself here — nothing hard, just more of them. We think that's a fair trade if your workload is file storage, laptop backups, and a photo library. Plan on virtual machines or 4K transcoding and the money is better spent further up this list.

This is the cheapest way into four bays, and Asustor spends the money where a first NAS actually needs it: a 2.5-gigabit Ethernet port, RAID 0/1/5/6 support, and a quad-core Realtek processor aimed at file serving rather than app hosting. For a backup target and a private folder you can reach from a phone, that covers the job. Three USB ports mean you can pull an old external drive's contents straight across, which is how most first weekends with one of these goes.

The 2GB of DDR4 is where the price shows. File shares, scheduled backups, and Plex streaming fit comfortably; running Docker containers, a virtual machine, or several apps at once does not, and a memory figure this small is the honest reason why. Two other things come with the low price: the Realtek chip is the least capable processor in this set, and Asustor's ADM has a smaller app catalog than DSM or QTS. None of that reaches a household that wants the files stored and the laptops backed up.

Four hard-drive bays and four M.2 NVMe slots in one desktop chassis: the AS6804T gives you eight drive positions where the rest of this set tops out at six or four. The hardware is just as far ahead — an AMD Ryzen V3C14 quad-core at 3.8GHz, 16GB of DDR5 with ECC, dual 5GbE plus a 10GbE port, and five USB ports.

That layout is built for one workflow: edit from the SSDs, archive to the hard drives, without a second enclosure on the desk. ECC memory is the spec most buyers skip, and on a machine that runs for months between reboots it's the difference between an error the system corrects and a file it doesn't. ADM is a capable interface with a smaller app catalog than DSM, and this is a box that invites you to run services on it.

Price is the whole question. You pay a premium over everything else here, and for file serving and photo backup you won't feel it, because the UGREEN DXP4800 Plus handles those for less than half as much. The AS6804T earns its keep when the NAS is a workstation: video projects, virtual machines, and datasets that cross the network at 10-gig speed all day. If that isn't your week, the four extra M.2 slots are capacity you'll never open.