Seagate Exos vs IronWolf for NAS: Ratings, Part Numbers and Noise at 12TB and 16TB

Exos vs IronWolf for NAS: what each data sheet rates the drive for

Start with what Seagate rates each line to do, because that is where the two part company most plainly. The IronWolf sheet covers drives up to 16 TB and says every IronWolf is rated for a 180TB/year workload and 1M hours MTBF, with a 3-year limited warranty. The Exos X24 sheet gives a 5-year limited warranty, 2.5 million hours MTBF and a 0.35% AFR across its 12 TB to 24 TB models, and the X24 SATA manual sets a maximum rated workload of under 550TB a year.

The workload row is the one to think about. Seagate's X24 manual defines its figure as terabytes transferred per year, or per 8,760 power-on hours, and puts the X24's ceiling just under 550TB. IronWolf's 180TB is about a third of that. If your NAS will read and write more than 180TB in a year, an IronWolf is being asked to do more than its sheet covers, while an X24 still has room on paper.

Both lines are CMR on Seagate's own documents, so recording technology does not separate them at these sizes. MTBF is a population rating, not a promise about the drive in your bay, and the warranty term is what decides who pays if one fails early.

Seagate Exos vs IronWolf at 12TB and 16TB, part number by part number

The IronWolf sheets stop at 16 TB, so 12 TB and 16 TB are the sizes where both lines have a current Seagate sheet to set side by side. Each row is one part number. Sustained rate is the maximum at the outer diameter, as both sheets label it, and idle is the average figure each sheet prints. IronWolf figures here come from sheet DS1904.22-2404US.

Two things stand out. At 12 TB the Exos has twice the cache and a higher sustained rate, at 6.3 W idle against the IronWolf's 5.1 W. At 16 TB the two IronWolf part numbers on DS1904.22 are not the same drive on paper: ST16000VN003 has 512 MB of cache and idles at 6.8 W, above the Exos X24, whilst ST16000VN001 has 256 MB and idles at 5.1 W.

Seagate's newer IronWolf sheet, DS1904.23-2509US from September 2025, lists ST16000VN001 as its only 16 TB model, with columns for 16, 12, 10 and 8 TB and the same 180TB/year rate limit throughout. On that sheet ST16000VN001 and ST12000VN0008 both idle at 5.1 W. A listing that says only IronWolf 16TB could still be either 16 TB number, so read the part number on the row.

The older DS1904.22 sheet also carries a 14 TB model, ST14000VN0008, with 256 MB, 240 MB/s and 5.1 W idle, all at 7200 RPM like the 12 TB and 16 TB models. The X24 has no 14 TB model, so that size has no Exos row here. Above 16 TB only Exos continues: the X20 sheet lists ST20000NM007D and ST18000NM003D on SATA with 256 MB of cache, a 285 MB/s sustained rate and 5.4 W idle, below the X24's 6.3 W.

IronWolf vs Exos noise: why 28 dBA and 2.8 bels are not the same scale

Noise matters more in a NAS that lives in a study than in a rack, and it is the comparison most likely to be read wrongly. The IronWolf data sheet prints acoustics in dBA. The Exos figures come from Seagate's product manuals, in bels, and the X24 SATA manual defines them as overall A-weighted acoustic sound power levels with no pure tones.

We have not found a document that states which quantity the IronWolf dBA figure measures. Seagate's X24 manual says its performance seek test places the drive in seek mode only. We have not found a document that converts bels to dBA either, so moving the decimal point to read 2.8 bels as 28 dBA would be our arithmetic, not Seagate's statement.

We do not rank these drives on noise. The only safe readings are inside one sheet: the IronWolf ST16000VN003 prints 2 dBA more at seek than ST16000VN001, and every Exos X24 SATA model shares one pair of figures.

Exos vs IronWolf prices on Amazon.co.uk: new listings by price per TB

Prices are pounds sterling inc VAT from Amazon.co.uk. The first block sets the two lines at the matched sizes; a dash means that side has no in-stock row at that size at this moment. The full tables below take every capacity, lowest price per TB first.

The IronWolf table leaves out IronWolf Pro part numbers, which begin NT0 or NE0, even where a seller's title says only IronWolf. The Exos table is wider than the X24 rows above: it takes SAS models, 2.5-inch Exos rows and older generations, and it leaves out titles carrying NM000C or NM002C. Check the interface, capacity and part number on any row before setting it against an IronWolf. The Recording column prints a technology only where a document ties it to the part number; CMR in an Amazon title is the seller's claim.

Exos vs IronWolf for NAS: choosing from the listings

• If your yearly reads and writes could pass 180TB, the IronWolf rating does not cover that workload; the Exos X24 manual's limit is under 550TB a year.
• If the warranty term decides it, the sheets give IronWolf 3 years and Exos X24 5 years.
• If idle power matters across several bays, compare part numbers, not lines: ST16000VN001 idles at 5.1 W, the Exos X24 at 6.3 W and ST16000VN003 at 6.8 W.
• If you need more than 16 TB a drive, the IronWolf sheets end there and Exos continues.

Whether a given NAS accepts either drive is a question for the NAS maker's own compatibility list. Seagate's wider range sits on Seagate Exos and Exos X24; the step up within the NAS line is on IronWolf vs IronWolf Pro, and the Pro against Exos on Exos vs IronWolf Pro.