NAS hard drives: exact models, capacity and compatibility

Four exact CMR drive candidates

These are bounded examples for an HDD shortlist. The linked manufacturer specifications identify all four as 3.5-inch SATA drives using conventional magnetic recording (CMR). That establishes the stated recording method; it does not establish noise, real-world speed or compatibility with every NAS.

• WD Red Plus WD40EFPX, 4 TB: WD specifies CMR, SATA and a 180 TB/year workload rating for this exact model.
• WD Red Plus WD80EFPX, 8 TB: the larger-capacity example is also specified as CMR with a 180 TB/year workload rating. Keep the full model number when comparing an offer.
• Seagate IronWolf ST4000VN006, 4 TB: the exact-model column in Seagate's datasheet specifies CMR, SATA 6 Gb/s and a 180 TB/year workload rating. The reviewed datasheet is a 2022 EMEA document; it establishes these hardware specifications, not a current US sales package.
• Synology Plus HAT3300-4T, 4 TB: Synology specifies a CMR, SATA 6 Gb/s drive. Its compatibility lists give us an additional, model-specific check below.

We have not established tested NAS compatibility for the two WD models or ST4000VN006 in this guide. Check the exact SKU with the NAS vendor before ordering. A workload rating is the manufacturer's stated usage allowance, not a measured lifespan or a guarantee against failure.

Check the actual NAS and firmware

On 14 September 2026, Synology's official compatibility data listed HAT3300-4T with PL01 firmware for both the DiskStation DS225+ and DiskStation DS925+. Reopen the DS225+ list or DS925+ list and read the drive's installation notes before purchase. This specific entry does not certify other HAT capacities, firmware versions or NAS models.

Synology's current policy for DSM 7.3 and above allows unlisted HDDs for new storage pools on 2025-and-later DiskStation Plus models. An unlisted drive is still distinct from one on the compatibility list; explicitly incompatible drives are another case. Check the installed DSM version. Do not extend that HDD policy to M.2 NVMe storage pools or cache, which have separate restrictions.

For the UGREEN NASync DXP2800 and DXP4800 Plus, use UGREEN's compatibility selector with the exact enclosure and drive model. UGREEN says an unlisted component has not been verified for basic interoperability with that NAS; absence is not proof of incompatibility. For a QNAP TS-264, select that model in QNAP's compatibility list. A WD or Seagate specification sheet cannot replace either vendor's test record.

Budget for usable storage and backup

Start with your current data, expected growth and a separate backup destination. Two 4 TB drives mirrored together provide one drive's nominal capacity before formatting and system overhead. They do not provide 8 TB of usable mirrored storage. For larger arrays, use the chosen NAS vendor's calculator for the exact RAID or storage-pool layout.

Leave room for snapshots and future files. Record the intended expansion route before filling every bay: adding a drive, replacing drives and changing the RAID layout have different requirements. Read the enclosure's storage instructions for that operation.

Redundancy can help a supported array continue through a drive failure. It does not create an independent copy of deleted, encrypted or corrupted files. Keep a separate backup and verify that you can restore it before treating the NAS as your only working store.

Check the delivered drive before moving data

1. Match the label's full model number and capacity to your order and the compatibility record.
2. Check the installed firmware, DSM/QTS/UGOS version and any vendor installation notes.
3. Run the NAS vendor's drive-health checks and inspect any compatibility warnings before copying the only copy of important data.
4. Create the intended storage layout, configure alerts and complete a sample backup restoration.

Use the NAS enclosure comparison for the box itself, then read the UPS guide to plan how that box will stop safely during a power failure.