HC590 versus HC680 is the most important WD Ultrastar decision in this batch because it is not merely 26TB versus 28TB. It is CMR versus UltraSMR/host-managed SMR.
The 28TB drive offers more density. The 26TB drive is the conventional enterprise path. Capacity alone should not decide this purchase.
Choose HC590 for conventional servers, NAS, ZFS, general Ceph and mixed workloads that expect normal CMR behavior. Choose HC680 only when the full storage stack supports host-managed SMR/zoned writes and the workload is controlled, sequential or append-heavy.
Use this as the procurement-level screen before looking at live price rows.
| Decision point | Ultrastar HC590 26TB | Ultrastar HC680 28TB |
|---|---|---|
| Architecture | CMR/ePMR | UltraSMR / host-managed SMR |
| Capacity | 26TB | 28TB |
| Interface | SATA and SAS variants | SATA 6Gb/s |
| Cache | 512MB | 512MB |
| Sequential transfer | 302MB/s max | 265MB/s max |
| Best workload | General enterprise storage | SMR-aware bulk and sequential storage |
| Workloads to avoid | None specific to recording method | Normal NAS, unqualified RAID, random-write pools |
| Decision metric | Compatibility first | Host-managed SMR support first |
This shows the capacity delta only. The financial answer comes from the live $/TB rows on the page.
| Drive count | Ultrastar HC590 26TB raw | Ultrastar HC680 28TB raw | Raw delta |
|---|---|---|---|
| 4 bays | 104TB | 112TB | 8TB |
| 6 bays | 156TB | 168TB | 12TB |
| 8 bays | 208TB | 224TB | 16TB |
| 12 bays | 312TB | 336TB | 24TB |
No exact in-stock live row is currently matched for WUH722626ALE6L4 / WSH722880ALN6L4. Relevant live alternatives are shown for pricing context; verify qualification before treating any row as a substitute.
Live prices · updated about once a day · last checked 24 min ago · one side may be unavailable; alternatives are not exact OEM replacements
| Model | Capacity | Recording | RPM | Workload TB/yr | Warranty | $/TB | Price | |
|---|---|---|---|---|---|---|---|---|
| 3TB HUS724030ALS640REFURB This offer: sold by Tech on Time (SN RECORDED) · Amazon says Used / LikeNew | 3TB | UNVERIFIED | 7,200 | — | — | $15.13 | $45 | Buy on Amazon |
| 3TB HUS723030ALS640REFURB This offer: sold by Tech Original · Amazon says Used / Good · title says Renewed | 3TB | UNVERIFIED | 7,200 | — | — | $18.33 | $55 | Buy on Amazon |
| 10TB HUH721010AL5200REFURB This offer: sold by Computer Supply · Amazon says Used / LikeNew | 10TB | UNVERIFIED | 7,200 | — | 5 yr | $23.50 | $235 | Buy on Amazon |
| 14TB WUH721414AL5204REFURB This offer: sold by Dealforless · Amazon says Used / Good | 14TB | UNVERIFIED | 7,200 | 550 | 5 yr | $26.79 | $375 | Buy on Amazon |
| 14TB WUH721414ALE604REFURB This offer: sold by Worldwide Product Importer · Amazon says New / New · title says Renewed | 14TB | UNVERIFIED | 7,200 | — | — | $27.14 | $380 | Buy on Amazon |
| 4TB HUS726040ALS210REFURB This offer: sold by Amazon Resale · Amazon says Used / LikeNew · Amazon Resale's note: No item damage observed during inspection. Item will come in original packaging. | 4TB | UNVERIFIED | 7,200 | — | — | $27.20 | $109 | Buy on Amazon |
| 14TB WUH721414ALE604REFURB This offer: sold by Worldwide Product Importer · Amazon says New / New · title says Renewed | 14TB | UNVERIFIED | 7,200 | — | — | $27.86 | $390 | Buy on Amazon |
| 12TB HUH721212ALE601REFURB This offer: sold by ANYHDD · Amazon says New / New · title says Renewed | 12TB | UNVERIFIED | 7,200 | — | — | $28.29 | $339 | Buy on Amazon |
Workload rating is recorded per part number from the manufacturer's published data for that exact model where available, 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.
This table is computed from live DatacenterDisk rows when an exact in-stock match exists. It is intentionally blank for unavailable models rather than filled with stale prices.
| Live model | Drive price | $/TB | 1 drive | 4 drives | 8 drives | 12 drives |
|---|---|---|---|---|---|---|
| No exact in-stock row is available right now. Use the availability table for nearby live alternatives, then re-check the exact model before ordering. | ||||||
HC590 records data conventionally. HC680 raises density by using UltraSMR, and WD's HC680 data sheet explicitly explains host-managed SMR. That difference changes how the host has to write data.
With CMR, a storage stack can issue normal random block writes. With host-managed SMR, software must respect zone behavior and write patterns. If your stack does not do that, the higher capacity is the wrong bargain.
HC590 is the safer choice for mixed file shares, backup targets with random metadata updates, VM-adjacent storage, conventional RAID, many ZFS deployments and general enterprise shelves.
HC680 fits systems that deliberately stage and sequence writes: object stores, content libraries, replication targets and data-center retention tiers where software is already built around SMR.
HC680 adds 2TB per bay over HC590. In a 60-bay shelf that is 120TB raw. That is real rack-density value for a platform already engineered for SMR.
For a small buyer, the engineering cost can exceed the capacity gain. Do not let a lower price per raw TB override compatibility.
No. HC590 is CMR; HC680 is UltraSMR/host-managed SMR and requires compatible host behavior.
HC590, unless you have a specifically validated SMR-aware design. Conventional TrueNAS pools should not assume HC680 compatibility.
No. Price per TB is the first screen, not the whole decision - for the Ultrastar HC590 vs HC680 specifically: match recording method, interface, bay count, firmware support, warranty position and rebuild risk before accepting the cheapest row.
Specification claims on this page were checked against the pages below on 1 September 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.