The two enterprise nearline families from the two remaining drive manufacturers. Same class of product, same duty cycle, same SATA-or-SAS trap, and both with deep refurbished markets. Neither is categorically better, so the decision is a price question at your capacity — and the table below answers it live. Right now Exos is cheaper at 1 of 7 directly comparable capacities and Ultrastar at 6.
Prices updated · live figures update every 4-5 hours
| Capacity | Exos new | Exos refurb | Ultrastar new | Ultrastar refurb | Cheaper | Buy |
|---|---|---|---|---|---|---|
| 12TB | $45.37 | — | $28.33 | $25.00 | ULTRASTARby 45% | ExosUltra |
| 14TB | $42.86 | — | $35.71 | $25.71 | ULTRASTARby 40% | ExosUltra |
| 16TB | — | $39.84 | $45.28 | $32.81 | ULTRASTARby 18% | ExosUltra |
| 18TB | $37.55 | — | $44.14 | $28.89 | ULTRASTARby 23% | ExosUltra |
| 20TB | $40.00 | $33.50 | $48.09 | $31.00 | ULTRASTARby 7% | ExosUltra |
| 22TB | $29.55 | — | $37.73 | $39.91 | EXOSby 22% | ExosUltra |
| 24TB | $40.00 | $29.17 | $45.83 | $27.88 | ULTRASTARby 4% | ExosUltra |
All figures are $/TB, live, cheapest in-stock listing per family per condition. “Cheaper” compares the best price either family offers at that capacity in any condition, and the Buy buttons go to that cheapest listing on each side. Currently Exos is cheaper at 1 of these 7 capacities and Ultrastar at 6.
Not scored above because only one family is in stock at that capacity: 1 Exos-only (30TB) · 6 Ultrastar-only (1.2TB, 3TB, 4TB, 6TB, 8TB, 10TB). Comparing a live price against an absent one is not a comparison, so those rows are counted rather than scored — and the gap itself is worth knowing when you are choosing a capacity.
Seagate and Western Digital are the two remaining manufacturers of hard drives at scale, and Exos and Ultrastar are their competing enterprise nearline lines. They exist to do the same job: run continuously in a multi-drive enclosure, at a published workload rating, for years.
That similarity is not marketing convergence — it is what the market demands. The buyers who set the specification for both lines are hyperscale operators purchasing by the pallet, and they want the same things from both vendors. What reaches retail is the overflow from that market, on both sides.
So the interesting variable is not engineering philosophy. It is which family happens to be cheaper at your capacity, on your condition track, this week — and that moves with supply rather than with anything about the drives.
Reliability. We publish no failure rates for either family. We have not run a fleet study; published third-party fleet statistics are not ours to restate as our own finding; and a failure rate attached to a model rather than to a population is not something an individual buyer can act on. Anyone telling you one of these families is more reliable than the other is generalising from a sample you cannot inspect.
Performance. No transfer rates, no seek figures, no benchmark comparisons anywhere on this page. These are nearline drives at the same rotational speed class doing sequential work, and a benchmark difference between them would not change which one you should buy.
What is left after removing those two is price, availability, interface and condition — which is, conveniently, all any buyer actually decides on.
Both families have deep second-hand markets, and the table above prices both tracks on both sides. What moves that market is fleet decommissioning cycles rather than anything about the drives, which means the refurbished answer can differ from the new answer at the same capacity in the same week.
The practical instruction is to read the row rather than the family. A capacity where Ultrastar wins on new can be one where Exos wins on refurbished, and if you are buying refurbished — which for an array with real redundancy is frequently the right call — the new-price comparison is simply not the one that concerns you. Our recertified guide covers what the grades mean.
Seagate and WD each ship the same capacities in SATA and SAS under names that differ by very little. A SAS drive will not work on a SATA-only backplane or a desktop SATA port, and the connector is keyed to prevent it. The reverse is fine and is designed in: a SAS backplane accepts SATA drives, which is why a used enterprise chassis can be filled with cheap SATA capacity.
Check the interface on the specific listing whichever family you choose. Our SAS versus SATA guide covers the asymmetry, and the used server guides document which backplane each machine was built with — the same question from the other end.
Live prices · updated every 4-5 hours · last checked 3 min ago · cheapest per terabyte, both condition tracks
| Model | Capacity | Recording | RPM | Workload TB/yr | Warranty | $/TB | Price | |
|---|---|---|---|---|---|---|---|---|
| 24TB ST24000NM002HREFURB | 24TB | CMR | 7,200 | 550 | 5 yr | $29.17 | $700 | Buy |
| 22TB ST22000NM001E | 22TB | CMR | 7,200 | — | 5 yr | $29.55 | $650 | Buy |
| 20TB ST20000NM007DREFURB | 20TB | CMR | 7,200 | — | 5 yr | $33.50 | $670 | Buy |
| 18TB ST18000NM003D | 18TB | EPMR | 7,200 | 550 | 5 yr | $37.55 | $676 | Buy |
| 16TB ST16000NM002GREFURB | 16TB | CMR | 7,200 | 550 | 5 yr | $39.84 | $637 | Buy |
| 24TB ST24000NM002H | 24TB | CMR | 7,200 | 550 | 5 yr | $40.00 | $960 | Buy |
| 20TB ST20000NM002H | 20TB | CMR | 7,200 | — | 5 yr | $40.00 | $800 | Buy |
| 30TB ST30000NM004K | 30TB | CMR | 7,200 | 550 | 5 yr | $40.00 | $1200 | Buy |
Workload rating is recorded per part number from Seagate's datasheet for that exact model, not blanketed across the line — two drives of the same capacity can differ because they are different generations. A dash means the figure is not stated for that listing. Recording technology comes from the manufacturer's published CMR/SMR list; a model absent from that list is shown as UNVERIFIED rather than guessed. Rows priced above 3× this line's in-stock median are flagged and excluded from the winner callout and from every median we compute.
Live prices · updated every 4-5 hours · last checked 3 min ago · the same ranking, computed the same way, so the two are comparable
| Model | Capacity | Recording | RPM | Workload TB/yr | Warranty | $/TB | Price | |
|---|---|---|---|---|---|---|---|---|
| 3TB HUS724030ALS640REFURB | 3TB | CMR | 7,200 | — | — | $15.13 | $45 | Buy |
| 4TB HUS726040ALS210REFURB | 4TB | CMR | 7,200 | — | — | $18.13 | $73 | Buy |
| 3TB HUS724030ALA640REFURB | 3TB | CMR | 7,200 | — | — | $20.00 | $60 | Buy |
| 4TB HUS726040ALS210 | 4TB | CMR | 7,200 | — | — | $20.00 | $80 | Buy |
| 10TB HUH721010AL5200REFURB | 10TB | CMR | 7,200 | — | 5 yr | $23.50 | $235 | Buy |
| 12TB HUH721212ALE604REFURB | 12TB | CMR | 7,200 | 550 | 5 yr | $25.00 | $300 | Buy |
| 14TB WUH721414AL5204REFURB | 14TB | CMR | 7,200 | 550 | 5 yr | $25.71 | $360 | Buy |
| 14TB WUH721414ALE604REFURB | 14TB | CMR | 7,200 | — | — | $25.71 | $360 | Buy |
Workload rating is recorded per part number from Seagate's datasheet for that exact model, not blanketed across the line — two drives of the same capacity can differ because they are different generations. A dash means the figure is not stated for that listing. Recording technology comes from the manufacturer's published CMR/SMR list; a model absent from that list is shown as UNVERIFIED rather than guessed. Rows priced above 3× this line's in-stock median are flagged and excluded from the winner callout and from every median we compute.
Fix your capacity and your condition track first, then read that row of the table and buy the cheaper side. That is genuinely the whole method, and it is more reliable than brand preference because it uses today's prices rather than last year's reputation.
If you are filling an array, consider deliberately splitting between the two. Mixing manufacturers means a single manufacturing batch problem cannot take out every drive in the array at once, and since the two families are equivalent in class there is no cost to doing it.
The Exos hub · The Ultrastar hub · Exos price verdicts · Ultrastar price verdicts · Exos against IronWolf
They are the same class of product from the two remaining hard drive manufacturers, and neither is categorically better. Both are enterprise nearline drives built for continuous duty in multi-drive enclosures, both ship in SATA and SAS, and both have deep refurbished markets. The honest answer for a buyer is that the decision is a price question at your capacity on your condition track, which is why the table on this page computes it live rather than declaring a winner.
It varies by capacity and it changes week to week, which is precisely why we compute it rather than write it. The table above shows both families at every capacity where we hold live prices, with new and refurbished separated, and marks which side is cheaper at each. Capacities where only one family is in stock are shown but not scored - comparing a live price against an absent one is not a comparison.
They are competing implementations of the same idea rather than the same drive. Both use conventional recording across most of their range, both are helium-sealed at higher capacities, and both publish workload ratings for continuous duty. Seagate's frontier capacities use its HAMR-based Mozaic platform. We do not publish comparative reliability figures for either - we have not run a fleet study and a failure rate attached to a model rather than a population is not something a buyer can act on.
Yes, and for a ZFS or similar array it is arguably good practice. Mixing manufacturers means a manufacturing batch problem cannot take out your whole array at once. What matters far more than the badge is that capacities match, recording technology is conventional throughout, and the interface suits your backplane. A mixed array of two enterprise lines is a normal, sensible build.
Both are deep, because both come out of datacentre fleets in batches. The table above shows refurbished prices for each family side by side where we hold them, and the answer moves with whatever fleets have recently been decommissioned rather than with anything about the drives. Check both, at your capacity, on the day you buy.
No - both families ship the same capacities in SATA and SAS, and both make the mistake easy by naming the variants very similarly. A SAS drive will not work on a SATA-only backplane or a desktop SATA port; a SAS backplane accepts SATA drives. Check the interface on the specific listing regardless of which family you choose.
Specification claims on this page were checked against the pages below on 4 August 2026. Where a widely-repeated figure did not survive that check, we report what the source says now and say so in the text rather than repeating the familiar number.