This editorial assessment uses current manufacturer documentation and CCTV system-design principles. We have not claimed hands-on laboratory testing. Specifications, firmware and regional availability can change; verify the linked source before buying.
- Designed for 24/7 surveillance writes
- CMR recording technology
- Up to 180 TB/year workload rating
- Capacity may be short for several 4K cameras
- A single disk provides no redundancy
WD Purple 4TB: key specifications
- Specification
- 4 TB
- Specification
- 3.5-inch SATA
- Specification
- CMR
- Specification
- Up to 180 TB/year
- Specification
- 3-year limited warranty
Where WD Purple 4TB fits
WD Purple is built for the continuous, multi-stream write pattern of video recorders rather than the stop-start workload of an ordinary desktop. Western Digital lists AllFrame firmware, up to 180 TB per year workload and support for many camera streams.
The 4 TB capacity is neither large nor small without a bitrate calculation. Four cameras averaging 4 Mbps each generate roughly 173 GB per day before overhead, putting 4 TB in the region of three weeks rather than months.
CMR recording technology is a positive for predictable sustained writes. Recorder compatibility must still be checked by model, firmware and maximum supported disk size before purchase.
Drive health monitoring does not make one disk a backup. Deletion, theft, recorder failure and catastrophic disk faults can still remove footage; important exports need a separate controlled copy.
A sensible mainstream NVR drive when 4 TB meets the measured retention target and one disk is not mistaken for a backup.
Western Digital WD Purple specifications
Use the manufacturer’s current documentation to confirm hardware revisions, regional features and compatibility.
Open official specifications ↗We did not find a sufficiently clear, model-specific independent video to recommend for this product. We will not attach a loosely related or promotional clip just to fill the space.