HAT5320 and HAS5320 are both Synology enterprise HDD families, but they are not interchangeable. HAT5320-24T is SATA. HAS5320-24T is SAS.
That interface difference controls system compatibility, backplane requirements, redundancy design and spare strategy. A 3.5-inch tray fit does not make a SAS drive work in a SATA-only NAS.
Choose HAT5320-24T for Synology SATA systems, including DiskStation and RackStation models whose compatibility list supports that drive. Choose HAS5320-24T for SAS-capable Synology enterprise systems where SAS pathing and qualification are required. Do not buy HAS5320 for a normal SATA DiskStation.
Use this as the procurement-level screen before looking at live price rows.
| Decision point | HAT5320 24TB | HAS5320 24TB |
|---|---|---|
| Interface | SATA 6Gb/s | SAS 12Gb/s |
| Capacity | 24TB | 24TB |
| Primary model | HAT5320-24T | HAS5320-24T |
| Rotational speed | 7200 RPM | 7200 RPM |
| Max sustained transfer | 309MB/s typical | 309MB/s typical |
| Workload / warranty | 550TB/year / 5 years | 550TB/year / 5 years |
| Best environment | Synology SATA NAS/storage systems | Synology SAS-capable enterprise systems |
| Primary advantage | Broader SATA bay fit | SAS pathing and enterprise rack qualification |
| Main limitation | No SAS dual-port behavior | Will not work in SATA-only bays |
This shows the capacity delta only. The financial answer comes from the live $/TB rows on the page.
| Drive count | HAT5320 24TB raw | HAS5320 24TB raw | Raw delta |
|---|---|---|---|
| 4 bays | 96TB | 96TB | 0TB |
| 6 bays | 144TB | 144TB | 0TB |
| 8 bays | 192TB | 192TB | 0TB |
| 12 bays | 288TB | 288TB | 0TB |
No exact in-stock live row is currently matched for HAT5320-24T / HAS5320-24T. Relevant live alternatives are shown so the page does not collapse into an empty catalogue.
Live prices · updated every 4-5 hours · last checked 5 hr ago · one side may be unavailable in exact live stock
| Model | Capacity | Recording | RPM | Workload TB/yr | Warranty | $/TB | Price | |
|---|---|---|---|---|---|---|---|---|
| 12TB HAS5300-12T | 12TB | CMR | 7,200 | — | 5 yr | $55.83 | $670 | Buy |
| 16TB HAT5310-16T | 16TB | CMR | 7,200 | — | 5 yr | $63.25 | $1012 | 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 |
|---|---|---|---|---|---|
| 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. | |||||
Both 24TB models give the same raw density: 96TB in four drives, 192TB in eight drives, 288TB in twelve drives and 576TB in twenty-four drives. The interface decides the purchase.
HAT5320 is SATA. HAS5320 is SAS. SAS can support enterprise pathing, redundant-controller designs and rackmount storage architectures, but only when the host system is built for it.
HAT5320 is the correct first-party Synology choice for SATA bays. That includes many DiskStation and RackStation configurations, provided the exact system compatibility list includes the model. It is also the family most buyers mean when they ask for a Synology-branded hard drive for a desktop NAS.
For small business and prosumer Synology deployments, SATA is often enough. The drive's sequential transfer rate sits far below the interface ceiling, so SAS is not a magic speed upgrade for ordinary file storage.
HAS5320 belongs in systems designed around SAS. Synology's SAS page positions HAS drives with enterprise systems such as HD, SA and UC class platforms, where controller pathing, high availability and rackmount design matter.
In those environments, SATA may remove redundancy or fail qualification. HAS5320 is not overkill there; it is the interface class the system expects.
Synology's drive policies are model and series dependent. The 2025+ DiskStation Plus, RS Plus and enterprise buckets do not treat unlisted drives identically, and pre-2025 systems are outside that policy table. HAT/HAS choices should therefore be verified against the exact Synology model and DSM documentation.
The important practical point is simpler: do not rely on a tray fit. A SAS drive needs a SAS-capable controller/backplane. A SATA drive does not provide SAS dual-port behavior in a dual-controller design.
HAT5320 can be the cheaper and more available first-party option because SATA systems are broader. HAS5320 can be more expensive or harder to source, but that premium is justified when the storage system requires SAS.
For spares, separate the pools. A HAT spare is not a HAS spare. If an HA system requires SAS, stocking SATA first-party drives does not solve the failure scenario.
HAT5320 is Synology's SATA enterprise HDD family. HAS5320 is the SAS enterprise HDD family for SAS-capable systems.
No. A SAS drive requires a SAS-capable controller and backplane. Physical 3.5-inch size is not enough.
Synology lists 309MB/s typical maximum sustained transfer speed for both 24TB models. SAS changes host pathing and redundancy, not the mechanical media speed by itself.
HAT5320 is enough when the Synology system uses SATA bays and the exact compatibility list supports the model.
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.