Choosing between a lower-cost NAS device and a New four-bay enclosure is the central decision in NAS storage & drives. The Seagate BlackArmor NAS 400 series is priced at USD 39.00, while the Synology DS423 is USD 374.99. The useful shortcut is clear: choose Seagate when upfront cost leads, or choose Synology when a four-bay enclosure is the priority.
Quick verdict
Pick the Seagate BlackArmor NAS 400 series if you want the lower purchase price and an External Drive format, and Used condition is acceptable. Pick the Synology DS423 if you want a New enclosure with four bays. The absolute price gap is $335.99, making this a choice between a lower-cost NAS device and a more fully specified enclosure rather than a close price match.
At-a-glance comparison
| Product | Price | Key deciding detail |
|---|---|---|
| Seagate BlackArmor NAS 400 series | USD 39.00 | Used; External Drive |
| Synology DS423 | USD 374.99 | New; four bays; HDD support |
Where each product wins
Seagate BlackArmor NAS 400 series
Seagate wins on purchase price. It is the easier choice for a shopper whose first constraint is keeping the initial spend low, provided the Used condition and External Drive format fit the plan. The product title also identifies it directly as a Network Attached Storage device, so its basic role is clear.
Synology DS423
Synology wins for shoppers who specifically want a multi-drive enclosure. Four bays and New condition give the DS423 a clearer fit for that use case, while HDD support adds a defined drive type to the setup. Its higher cost is easier to justify when those enclosure characteristics matter more than the lowest entry price.
Product notes
Seagate BlackArmor NAS 400 series
The Seagate BlackArmor NAS 400 series is the sensible pick when the goal is to keep the purchase price low while choosing a NAS device. Its Type is External Drive, a concrete format label that separates it from the enclosure-oriented Synology choice. The limitation is condition: Seagate is marked Used. That makes it a weaker match for anyone who specifically prioritizes a New unit, even though the lower price is compelling. The title also names the BlackArmor NAS 400 series directly, so the decision is easy to frame: choose Seagate for the lower-cost, external-drive route; choose Synology when New condition is more important than the initial outlay.
Synology DS423
The Synology DS423 is a good fit when its physical fit and drive format matter. The enclosure supports 2.5- and 3.5-inch form factors and HDDs, while Ethernet and PC compatibility add clear connection context. The limitation is that the DS423 is Diskless, so the enclosure itself is the focus rather than a drive-filled package. A shopper choosing Synology should therefore be comfortable treating the enclosure as the main purchase. When those form-factor and connection details are useful, Synology has the clearer brief; when they are not, its higher price is harder to justify.
Final choice by use case
- Lowest upfront cost: Choose the Seagate BlackArmor NAS 400 series, assuming Used condition and the External Drive format are acceptable.
- Multi-drive enclosure: Choose the Synology DS423 for its four bays and New condition.
- HDD-focused setup: Synology is the more clearly defined match because HDD support and 2.5- and 3.5-inch form factors are specified.
- Simple decision: Seagate is the price-led choice; Synology is the enclosure-led choice. The right pick depends on whether the $335.99 gap buys features you actually need.
