it is cheaper per terabyte and the drive is a desktop archive or media volume, where shingled recording is genuinely fine.
you want conventional recording at 4TB, which WD's own list supports and Seagate's BarraCuda at this capacity does not.
| ST4000DM004 | WD40EZAX | |
|---|---|---|
| Model number | ST4000DM004 | WD40EZAX |
| Capacity | 4TB | 4TB |
| Form factor | 3.5" | 3.5" |
| Recording technology | SMR | CMR |
| Rotational speed | 5400 RPM | 5400 RPM |
| Cache | 256 MB | 256 MB |
| Workload rate | 55 TB/yr | — |
| Warranty | 2 years | 2 years |
| Status | Current | Current |
Recording technology is highlighted because it is usually the actual differentiator, and each value comes from the manufacturer document linked on that model's page. A dash means the maker does not state that field. Prices are live and exclude out-of-stock listings.
4TB is one of the capacities where the two brands land on opposite sides of the recording question, and both are documented by their manufacturers.
Seagate's datasheet states shingled recording for the ST4000DM004, which is the 4TB BarraCuda you will be sold. It is 5400rpm with 256MB of cache.
Western Digital's client SMR list names its shingled models and no 4TB WD Blue appears on it, with the document closing by stating that all other capacity points use conventional recording. The WD40EZAX is therefore conventional under WD's own statement.
So at 4TB, unlike at 1TB, the brand does map onto the answer for the current models, which makes this the least ambiguous of these comparisons.
This is the capacity where the decision starts mattering more, because 4TB is a common size for exactly the two use cases that sit on opposite sides of the shingling question.
As a desktop media or archive volume, 4TB is a sensible size and shingled recording is a non-issue. Files arrive whole, are read many times and are rarely modified in place.
As an entry-level NAS drive, 4TB is also a common choice, and there the shingled drive is the wrong tool. Neither of these is a NAS-rated drive, but a conventional one at least does not sabotage a rebuild.
Shingled recording overlaps tracks to raise density, so modifying data under an existing track can force the tracks above it to be rewritten. That is invisible for sequential work and severe during a rebuild, which is hours of sustained writing with no idle time for the drive to reorganise.
4TB is a considerably better place on the cost-per-terabyte curve than 1TB or 2TB, which is the main reason to prefer it as a purchase regardless of brand.
Between these two specifically, price per terabyte on the day should decide it for desktop use, and the conventional recording should decide it for anything with a possible array future.
If the drive is definitely going into a NAS, neither is the right answer. WD Red Plus, Seagate IronWolf and Toshiba N300 all offer conventionally-recorded NAS-rated drives at 4TB, and the price difference buys a stated workload rating, a longer warranty and vibration handling.
The case against the WD40EZAX is that for a pure desktop archive you may be paying for conventional recording that never earns its premium, a media volume does not care. The case against the ST4000DM004 is more consequential: 4TB is a common entry-level NAS capacity, and this is the drive people put in one without checking, which is precisely the purchase the 2020 shingled-drive episode was about. Neither is a NAS-rated drive, so if that is the destination, both are the wrong answer.
Yes, per Seagate's own BarraCuda datasheet. It is the 4TB BarraCuda you will be sold, at 5400rpm with 256MB of cache. There is no current conventionally-recorded 4TB BarraCuda.
Yes, under Western Digital's own client SMR list, which names the shingled models and states that all other capacity points use conventional recording. No 4TB WD Blue appears on the shingled list.
Neither is a NAS-rated drive. The conventional one at least will not sabotage a rebuild, but both are desktop lines with desktop duty cycles and warranties. For an array, WD Red Plus, Seagate IronWolf or Toshiba N300 at 4TB are the drives specified for the job.
It sits considerably better on the cost-per-terabyte curve than 1TB or 2TB, so as a purchase it is usually good value. Whether it is enough depends on what you are storing; media and game libraries grow faster than most people expect.