Best NAS for Home: Four-Bay Picks and What to Skip

Choosing a home NAS comes down to four decisions and almost nothing else: how many bays, x86 or ARM, whether the box supports SHR, and whether you need ECC memory. Everything else on the specification sheet is either derived from those or is marketing. Get all four right and the enclosure will outlast two full sets of drives.

Three picks below at three genuinely different budgets, then the reasoning behind each of those four decisions. Remember throughout that the box is the small half of the purchase: four 8 TB NAS drives is roughly $1,400 on top of whatever the enclosure costs.

Best home NAS by experience level

Beginner Best for most homes

Synology

Synology DS225+ (2-Bay Diskless)

$364.99

DSM is still the most approachable NAS operating system, and two bays in SHR gives you one drive of redundancy without buying four drives on day one. Hardware transcoding is included.

Best for: A first NAS for photos, file sync and a modest media library.

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Intermediate Best four-bay

Synology

Synology DiskStation DS925+ (4-Bay Diskless)

$743.71

Four bays is the point where SHR starts paying for itself, because you can add a larger drive later and actually use the extra capacity instead of stranding it.

Best for: Households that expect their library to double, and anyone who wants SHR-2.

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Expert Enthusiast

Asustor

Asustor Lockerstor 4 Gen3 AS6804T (4-Bay, 10GbE)

$1,517.99

ECC memory, four M.2 slots and a 10GbE port. The specification is genuinely enthusiast grade, and so is the price.

Best for: People who already know they are network-limited and have the switch to match.

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How many bays should a home NAS have?

Bay count is the single specification you cannot fix later. You can add memory, add a network card in some units, add cache SSDs, and replace every drive. You cannot add bays to a chassis that does not have them, so the only remedy for running out is buying a second NAS and migrating.

Two bays gives you a mirror: one drive of usable capacity, one drive of redundancy, and no growth path except replacing both drives at once. Four bays is where the arithmetic starts working. Four drives under single parity gives three drives of usable capacity, and the same four drives can run double parity if you would rather have the safety.

Usable capacity is decimal TB. Your NAS reports these figures about 9.05 percent smaller because it counts in binary tebibytes, so 24 TB shows as 21.83 TiB. Run your own drive set through the RAID capacity calculator for exact numbers.

The usable-per-dollar column is the argument for four bays in one figure. A two-bay mirror gives up half its raw capacity to redundancy. Four bays under single parity gives up a quarter, which is 50 percent more storage per dollar of drives for the same protection against one failure. Six bays under double parity still beats a two-bay mirror, so the extra bays effectively pay for a second layer of safety for free.

x86 against ARM: what does the processor actually decide?

ARM NAS boards are cheap, quiet and idle around 8 W. They serve files perfectly well, and if that is genuinely all you want, they are not a compromise.

x86 buys you three things ARM generally cannot. Docker containers and virtual machines run against a far larger body of prebuilt images, and a great deal of self-hosted software ships x86 images only. Desktop-class single-thread performance makes the web interface feel responsive rather than sluggish, which matters more day to day than any benchmark. Most importantly, Intel x86 chips carry Quick Sync in their integrated graphics, the fixed-function video engine that makes hardware transcoding possible. Without it, every transcode falls to the general-purpose cores.

That last point is worth being concrete about, because it is where buyers most often regret the cheaper box. A NAS without Quick Sync can still stream video perfectly, as long as the client plays the file untouched. The moment something forces a conversion, and a phone on mobile data or a burned-in subtitle track will, the whole thing stutters. See best NAS for Plex for the full treatment.

What does a home NAS actually cost to run?

A NAS runs continuously, so idle draw matters far more than peak. Budget 6 to 9 W per 3.5 inch drive at idle and 8 to 10 W spinning up under load, plus the board: roughly 8 W for ARM, 15 to 20 W for a Celeron or N100, and 25 to 35 W for a Core i5 class board. Annual cost is W / 1000 x 8760 x tariff.

Drives estimated at 7 W each, mid-range for a 3.5 inch NAS drive at idle. Substitute your own tariff in the power draw calculator, which also handles spin-up load and SSD figures.

The useful conclusion is that the processor choice costs less than people fear. Moving from an N100 to a Core i5 in a four-bay box adds 13 W, which is $18 a year. That is not a reason to buy the weaker chip. Drive count is the bigger lever: going from four bays to eight adds 28 W of spindles, roughly $39 a year, which is still modest but compounds with the drive purchase itself.

Why is SHR the only scheme that makes rolling drive upgrades work?

Synology Hybrid RAID slices the drives horizontally at every distinct drive size and gives each horizontal band its own parity group. Standard RAID and every ZFS RAIDZ vdev do the opposite: they truncate every member down to the smallest drive and strand the excess.

Worked through on 2 TB, 3 TB and 4 TB drives with single parity: the band from 0 to 2 TB sits on all three drives and yields 4 TB, the band from 2 to 3 TB sits on two drives and yields 1 TB, and the band from 3 to 4 TB sits on one drive with nothing to protect it, so it is stranded. SHR gives 5 TB, RAID 5 gives 4 TB. That 1 TB gap is the whole pitch, and it grows as your drives diverge. Be clear about the limit though: with identical drives SHR is exactly RAID 5 and gains you nothing.

So why does it matter for a home NAS? Because home arrays are upgraded gradually, not replaced. Picture a four-bay array of 8 TB IronWolf drives that is filling up. You buy two 12 TB Red Plus drives and swap them in. Under ZFS or standard RAID you gain exactly zero additional capacity until the third and fourth drives are also replaced, because every member is truncated to the 8 TB smallest. Under SHR the 4 TB band shared by the two new drives becomes a mirrored band and yields 4 TB immediately.

That is the difference between an upgrade you can afford in stages and one you have to save up for in full. Our SHR against RAID 5 comparison works through several drive mixes side by side.

Does a home NAS need ECC memory?

ECC memory carries an extra parity bit per word so the memory controller can detect and correct single-bit errors before the data is written to disk. Ordinary memory silently passes the flipped bit through, and the array dutifully computes parity over corrupted data.

The honest assessment: ECC is real protection against a rare event, and how much you should pay for it depends entirely on what the array holds. For a photo or document archive you write once and read in ten years, a silently corrupted file is corruption you will not discover until it matters, and no amount of parity helps because the parity was computed over the corrupted version. For a media library of content that can be re-acquired, the same money is doing more work as a second parity drive or an offsite backup copy.

On memory quantity rather than type: 2 GB is enough for file serving and nothing else. Running a handful of containers wants 8 GB, and a virtual machine or two wants 16 GB. Memory is usually upgradeable, so it is the one specification you can safely under-buy at purchase, unlike bays.

What else do you need to budget for?

A NAS is rarely a single purchase. Three accessories turn up in almost every build and are worth planning for rather than discovering:

• A UPS. A NAS losing power mid-write is how filesystems get damaged. The CyberPower CP1350PFCLCD is the sensible size for a four-bay build, and pure sine wave output matters because power supplies with active power factor correction can refuse to run on the stepped waveform cheaper units produce. A 650 VA unit is enough for a two-bay NAS and a router. Note that VA is not watts: consumer units publish a power factor around 0.6 to 0.9, so a 1500 VA unit is often 900 W.
• A backup target. The array is copy one. A desktop external drive gives you copy two cheaply, and rotating a second one offsite gives you copy three.
• Network. 1GbE tops out around 113 MB per second real world, and a single 7200 rpm drive sustains 150 to 260 MB per second, so one drive already saturates gigabit. A 2.5GbE switch costs very little and roughly triples real transfer speed, which is the best value upgrade in most home labs.

RAID is not a backup. It protects against a drive dying and does nothing about deletion, ransomware, a controller writing garbage, theft, fire or flood. Size real copies with the 3-2-1 backup sizing calculator, remembering that you size the used data plus growth plus version history, not the array's raw capacity.

Who should not buy the Expert pick

The Asustor Lockerstor 4 Gen3 at $1,517.99 is a legitimately enthusiast-grade specification: ECC, four M.2 slots and a 10 gigabit port. Most people should not buy it, and the reason is arithmetic rather than snobbery. That box costs $774.28 more than the four-bay Synology. $774 is two more 8 TB drives, or the difference between four 8 TB drives and four 12 TB drives, which is 16 TB more usable capacity under single parity.

The 10 gigabit port is the specific trap. It only does anything if you already own a 10GbE switch and a 10GbE client, which is a further several hundred dollars, and even then a four-drive array of 7200 rpm disks tops out well short of the 1,100 MB per second the link can carry. Meanwhile 1GbE tops out around 113 MB per second and 2.5GbE around 280 MB per second, and 2.5GbE gear costs almost nothing now. Check 2.5GbE against 10GbE before assuming you need the faster port.

The four M.2 slots are the second trap. SSD caching improves benchmark figures far more than it improves anything a household actually does, because home workloads are mostly large sequential reads that a spinning array already serves faster than the network can carry.

Buy the Expert pick if you have already measured yourself hitting the network ceiling and own the switch, or if the NAS is doing double duty as a virtualisation host. Otherwise put that money into drives instead, which is the upgrade you will notice every day rather than the one you notice during large file copies. Equally, do not talk yourself down too far: the two-bay DS225+ is an excellent first NAS, but if you already know the library will double, four bays now costs less than four bays later plus a migration.

Related reading

• Best NAS hard drives for the half of the purchase that actually costs money
• Beginner home server setup for a complete first build, drives and accessories included
• First home server buying order for what to buy in which sequence
• Synology against QNAP for the software ecosystem question
• NAS against a DIY server if you are still deciding whether to buy an appliance at all
• Best NAS under $500 if the total budget including drives is the constraint