Seagate Exos 25TB versus 24TB is not a simple one-terabyte upgrade. The ST25000NM000E profile covered here is a host-managed SMR/ZAC drive, while the 24TB Exos X24 reference is the conventional CMR branch.
That makes compatibility the first decision and price the second. A 4.2 percent raw capacity gain can be valuable at fleet scale, but it is rarely worth changing storage architecture by accident.
Buy the 25TB ST25000NM000E only if your storage stack supports host-managed SMR and the extra capacity lowers system cost. Buy 24TB Exos X24 when you need conventional CMR behavior, broad enterprise compatibility or a safer replacement path.
Use this as the procurement-level screen before looking at live price rows.
| Decision point | Exos 25TB | Exos X24 24TB |
|---|---|---|
| Architecture | SMR / ZAC host-managed | CMR conventional enterprise |
| Capacity | 25TB | 24TB |
| Raw gain | +1TB per drive | Baseline |
| Interface | SATA 6Gb/s | SATA and SAS variants by model |
| Cache | 512MB | 512MB class by SKU |
| Best workload | Qualified sequential/bulk storage | General enterprise storage |
| Avoid for | Unqualified NAS, hardware RAID, random-write pools | Lowest possible slot count when SMR is already supported |
| Main purchase test | Host-managed SMR support first | Live $/TB and compatibility |
This shows the capacity delta only. The financial answer comes from the live $/TB rows on the page.
| Drive count | Exos 25TB raw | Exos X24 24TB raw | Raw delta |
|---|---|---|---|
| 4 bays | 100TB | 96TB | 4TB |
| 6 bays | 150TB | 144TB | 6TB |
| 8 bays | 200TB | 192TB | 8TB |
| 12 bays | 300TB | 288TB | 12TB |
The gain over 24TB is small per disk but visible in larger chassis.
| Drive count | 24TB raw | 25TB raw | Extra raw capacity |
|---|---|---|---|
| 8 drives | 192TB | 200TB | 8TB |
| 12 drives | 288TB | 300TB | 12TB |
| 24 drives | 576TB | 600TB | 24TB |
| 60 drives | 1440TB | 1500TB | 60TB |
One exact live row is currently matched for ST24000NM002H, but both sides of ST25000NM000E / ST24000NM002H are not simultaneously in exact live stock. Relevant live alternatives are shown below for pricing context.
Live prices · updated every 4-5 hours · last checked 7 hr ago · one side may be unavailable in exact live stock
| Model | Capacity | Recording | RPM | Workload TB/yr | Warranty | $/TB | Price | |
|---|---|---|---|---|---|---|---|---|
| 24TB ST24000NM002HREFURB | 24TB | CMR | 7,200 | 550 | 5 yr | $29.17 | $700 | Buy |
| 24TB ST24000NM000H | 24TB | CMR | 7,200 | 550 | 5 yr | $58.37 | $1401 | 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.
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 | 100TB raw target | 500TB raw target | 1PB raw target |
|---|---|---|---|---|---|
| ST24000NM002H | $700 | $29.17 | 5 drives / $3500 | 21 drives / $14700 | 42 drives / $29400 |
Buy ST25000NM000E when the deployment is already designed around host-managed SMR. The best examples are controlled bulk-storage systems, object-storage nodes, retention pools and ingest paths that can shape writes deliberately.
The economics work when fewer slots, shelves or rack units offset the cost of qualification. At 60 drives, the 25TB model adds 60TB raw over 24TB. In smaller arrays, that gain is usually not enough to justify architectural risk.
Buy Exos X24 when the environment expects conventional CMR block behavior. That includes many ZFS pools, hardware RAID shelves, backup servers, mixed file storage and NAS deployments that have not been qualified for host-managed SMR.
The 24TB drive can also be the better value when mature inventory beats the 25TB row on live cost per usable TB. Do not overpay for 1TB per bay unless bays are the expensive part of the system.
A 25TB host-managed SMR drive is not a universal spare for a 24TB CMR pool. The replacement drive has to match both capacity and media behavior requirements. If operations wants simple spare shelves, CMR is easier to manage.
If you do standardize on ST25000NM000E, document which hosts, HBAs, firmware paths and applications are qualified so the model is not accidentally used outside its intended stack.
No. The ST25000NM000E 25TB model covered here is host-managed SMR/ZAC, while the Exos X24 reference is conventional CMR.
One terabyte per drive, or 24TB raw in a 24-drive shelf.
The 24TB CMR Exos path is the safer default unless the ZFS design is specifically built and validated for host-managed SMR.
No. Price per TB is the first screen, not the whole decision. 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.