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NAS hard drives

Seagate IronWolf 4 TB, with three years of warranty and no rotational speed vs Western Digital Red Plus 4 TB, 5400 rpm, with five bullets and no second figure

Three published figures between two drives, and the one that matters most is on neither page.

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Same capacity, same interface, opposite silences. The Seagate IronWolf 4 TB publishes 1 million hours and a three-year limited warranty, and never gives a rotational speed. The Western Digital Red Plus 4 TB prints 5400 rpm and nothing else mechanical — no cache, no figure in hours, no term. Neither page says whether the drive records with overlapping tracks, which on a drive sold for a multi-bay enclosure is the question a rebuild turns on.

Seagate IronWolf 4 TB 3.5-inch NAS hard drive with a SATA connector

Seagate IronWolf 4 TB, with three years of warranty and no rotational speed

Wins 2 of 10

Check price

≈ $190 / £170 / 205 €

WD Red Plus 4 TB 3.5-inch NAS hard drive with a SATA connector

Western Digital Red Plus 4 TB, 5400 rpm, with five bullets and no second figure

Wins 1 of 10

Check price

≈ $195 / £205 / 210 €

Line by line

Compared on IronWolf 4 TB, with three years of warranty and no rotational speed Red Plus 4 TB, 5400 rpm, with five bullets and no second figure
Capacity 4 TB, in the maker’s unit; the 16 TB also printed is given as the range ceiling, not as this drive 4 TB, in the maker’s unit, no conversion applied
Recording method Not published — neither CMR nor SMR appears, on a drive sold for enclosures of up to eight bays, which is where the answer changes what a rebuild does Not published — neither CMR nor SMR appears, on a drive whose bullets are about behaviour inside a multi-drive enclosure
Stated workload rating Not published as a figure in terabytes per year — an enclosure ceiling of eight bays is given, which is a deployment limit rather than an annual duty Not published as a figure — parameters tuned for network storage workloads and continuous operation are named, with no annual figure behind either
Rotational speed Not published — no rpm figure appears, on a page that does publish an MTBF and a warranty term 5400 rpm, the only mechanical figure the page carries besides the capacity and the interface
Cache size Not published as a figure for this drive — up to 256 MB is printed in the same sentence as 16 TB, and both are range ceilings rather than values for the drive in the title Not published
Interface SATA at 6 Gb/s SATA at 6 Gb/s
Warranty length Three years, limited, with three years of a data recovery service named separately alongside it Not published — no term of any length, on a page that discusses total cost of ownership
Stated MTBF 1 million hours — a population statistic in hours, and neither the warranty term above it nor a lifespan Not published — reliability is described in words, as a drive designed for systems that run day and night
Stated idle power Not published Not published as a figure — less power than earlier models is claimed, which is a comparison against an unnamed baseline
Stated acoustic figure Not published as a figure — little to no noise and vibration is promised, with no decibel value behind it Not published — heat rather than noise is the subject

A tick means one listing published something the other did not, or published a better figure. It does not mean the product is better, and the column is not a score out of anything: a maker who says less loses lines here without losing a comparison. The two verdicts below are where the page is settled.

Which one, for whom

Buy the Seagate IronWolf 4 TB, with three years of warranty and no rotational speed

The IronWolf is the better-documented drive on the figures a buyer can use. Three years, limited, stated as a product warranty with the data recovery service named separately beside it — two terms, kept apart, which most pages here manage to blur. One million hours is a population statistic and worth reading as one. It never states a rotational speed, and the 256 MB and 16 TB printed on the page are range ceilings, not this drive.

Buy the Western Digital Red Plus 4 TB, 5400 rpm, with five bullets and no second figure

The Red Plus states 5400 rpm, which is genuinely useful — a slower drive in a multi-bay box is a cooler and quieter one — and then states nothing else. No cache, no figure in hours, no term of warranty, on a page that finds room to discuss total cost of ownership. Both drives leave the recording method unpublished, and on a shelf with only three drives in it, that is the gap neither maker fills.

The questions that come up before an order

Three published figures — which is which?

A warranty is a commercial term, and IronWolf states three years. An MTBF describes failures across a population under defined conditions, and IronWolf states 1 million hours. A workload rating is an annual duty, and neither of these publishes one. None of the three is a lifespan, and no two of them mean the same thing.

Does a mirrored pair of these count as a backup?

No. Redundancy means the enclosure carries on when a drive fails; it copies every write to both drives as it happens, including the ones you did not mean. A deleted file is deleted on both, and a fire or a theft takes both. A backup is a separate copy somewhere else — the array is what keeps the box running until you can replace a drive.

The full reviews

  • NAS hard drives

    Seagate IronWolf 4 TB, with three years of warranty and no rotational speed

    4 TB · SATA 6 Gb/s · 1 million hours MTBF · three-year warranty with data recovery · no rpm figure · range figures printed beside the model figures

    A four-terabyte drive for enclosures that publishes an MTBF, a warranty term and a recovery service, and whose only cache and capacity figures in the bullets belong to the range rather than to this model.

    Best for: A multi-bay enclosure where a published warranty and a recovery service matter more than knowing every figure, and where the drive will be one of several.

    ≈ $190 / £170 / 205 €

    Check price on Amazon Read the review
  • NAS hard drives

    Western Digital Red Plus 4 TB, 5400 rpm, with five bullets and no second figure

    4 TB · 5400 rpm · SATA 6 Gb/s · tuned for enclosure workloads · no cache, no MTBF, no warranty, no recording method

    A four-terabyte drive for enclosures whose title carries every figure the page has, and whose five bullets describe continuous operation, compatibility testing and lower running costs without printing a single value.

    Best for: A quiet enclosure in a lived-in room where the slower spindle is wanted deliberately, bought by someone who will get the remaining figures from the maker’s own datasheet.

    ≈ $195 / £205 / 210 €

    Check price on Amazon Read the review

Every price named in a summary was read on the date that review carries. What a shop asks today is shown beside the product, and it moves.