Western Digital DC HC550 16TB SATA Enterprise HDD

Name: Western Digital DC HC550 16TB SATA Enterprise HDD
Brand: Western Digital
SKU: DC HC550 16TB

Overview

The Western Digital DC HC550 at 16TB represents a meaningful density milestone: getting that capacity into a 3.5-inch SATA drive requires Western Digital's Energy-Assisted Magnetic Recording technology, which uses localized energy assist during writes to maintain track accuracy at areal densities that would otherwise cause reliability issues with conventional recording. Paired with CMR, this means the DC HC550 behaves predictably under every workload condition that an enterprise NAS or backup server will throw at it — no write penalty artifacts, no random I/O cliff, just consistent SATA 6Gb/s throughput at 7200RPM. At sustained sequential reads approaching 270MB/s, this drive is built for moving large blocks of data reliably, not for the sub-millisecond latency demands of a database transaction log.

The Triple Stage Actuator is the other engineering detail worth understanding: at 16TB, the platters are written at extremely high areal density, and fine head positioning accuracy directly affects read error rates over the drive's life. TSA provides finer control than dual or single-stage designs, which matters most during sustained operations on nearly-full platters. This drive is built for NAS arrays, backup targets, and media storage servers where capacity and sustained throughput take priority over IOPS. As a renewed unit with a 2-year seller warranty, it's a cost-effective path to high-capacity storage for secondary or tertiary storage tiers. Perform a full pre-deployment diagnostic — that's standard practice, not a caution unique to this drive.

Key Features

16TB capacity in a standard 3.5-inch form factor

CMR technology works with all capacity enterprise applications & environments

Industry’s first HDD with Energy-Assisted Magnetic Recording technology

Industry’s first Triple Stage Actuator

Backed by a 2-year seller warranty

Specifications

Brand

Western Digital

Model

DC HC550

Capacity

16TB

Form Factor

3.5-inch

Interface

SATA 6Gb/s

RPM

7200RPM

Recording Technology

CMR with Energy-Assisted Magnetic Recording (EAMR)

Actuator

Triple Stage Actuator (TSA)

Warranty

2-year seller warranty

Condition

Renewed

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Pros & Cons

👍 Pros

16TB CMR capacity is fully compatible with enterprise RAID controllers and NAS firmware that explicitly rejects SMR drives
7200RPM spindle speed delivers sustained sequential throughput suitable for backup targets, media storage, and large-file archival
Energy-Assisted Magnetic Recording achieves high areal density while maintaining CMR write reliability — no SMR trade-offs
Triple Stage Actuator improves head positioning precision at 16TB density, reducing read errors during sustained operation
3.5-inch standard form factor fits any compatible NAS bay, server, or DAS enclosure without adapter hardware

👎 Cons

Renewed condition requires mandatory pre-deployment SMART testing and surface scan — do not deploy directly into production arrays without verification
SATA 6Gb/s saturates at ~270MB/s sequential — for workloads requiring higher throughput, SAS alternatives exist at this capacity tier
At 16TB, a full RAID rebuild following drive failure will take 24–48 hours depending on array configuration, during which redundancy is reduced
Vibration compensation performance in multi-drive dense enclosures is not specified for the renewed unit — relevant in 12+ drive NAS chassis
No published workload rate (TB/year) rating confirmed for this specific renewed listing — verify before deploying in write-intensive environments

Frequently Asked Questions

What does CMR mean for this drive, and why does it matter for enterprise workloads?

CMR (Conventional Magnetic Recording) means tracks are written sequentially without overlapping, unlike SMR (Shingled Magnetic Recording). For enterprise applications — NAS arrays, RAID rebuilds, database write-heavy workloads — CMR delivers consistent write performance without the performance degradation SMR shows under sustained random writes.

What is Energy-Assisted Magnetic Recording (EAMR) and why does Western Digital call it an industry first?

EAMR uses a small amount of additional energy during the write process to stabilize the magnetic field, enabling higher areal density without sacrificing write accuracy. This is what allows 16TB in a standard 3.5-inch form factor while maintaining CMR reliability.

What interface does the DC HC550 use, and what throughput can I expect?

SATA 6Gb/s is the interface. At 7200RPM, sustained sequential reads typically approach 250–270MB/s — sufficient for NAS, backup, and archival use but not a replacement for NVMe in latency-sensitive applications.

What workloads is the Triple Stage Actuator (TSA) designed to improve?

The TSA provides finer head positioning control at high areal densities. In practice it improves track following accuracy on the 16TB platters, which reduces errors during sustained read/write operations compared to single or dual-stage actuator designs at equivalent density.

This is listed as renewed — what does that mean for a drive I'm putting into production storage?

Renewed enterprise HDDs have been tested and recertified, but for production use in RAID or NAS arrays, run an extended SMART diagnostic and a full surface scan before deployment. The 2-year seller warranty provides coverage, but enterprise practice is to verify any drive before trusting it with live data.