Product Description
Recertified Seagate Exos X18 12TB 3.5" SATA HDD – 7,200 RPM, 6Gb/s, 256MB Cache, ST12000NM000J
Enterprise-class storage at a recertified price — the Seagate Exos X18 12TB is a 7,200 RPM 3.5" SATA hard drive engineered for hyperscale deployments, high-density NAS systems, and sustained 24/7 workloads. With a 256MB multi-tier cache, sustained transfer rates up to 261 MB/s, a 2.5 million hour MTBF rating, and a 550TB annual workload capacity, this is genuine enterprise-grade storage. This unit has been professionally recertified and is covered by a 1-year PCBoost warranty.
Enterprise Performance at a Recertified Price Point
The Seagate Exos X18 is built from the ground up for continuous enterprise workloads — the environments where consumer and prosumer NAS drives routinely fall short. The 12TB capacity, 261 MB/s sustained transfer rate, and 7,200 RPM spindle speed position it firmly in the enterprise tier. Furthermore, the recertified format makes this level of performance accessible at a substantially lower cost than a new unit, making it an intelligent choice for budget-conscious builds that still demand enterprise reliability.
The Exos X18 achieves its 12TB capacity through a hermetically sealed, helium-filled enclosure. Helium's lower density compared to air reduces internal turbulence, allowing more platters to be stacked within the standard 3.5" form factor. This design also results in lower operating temperatures and reduced power draw compared to air-filled drives at equivalent capacities — a meaningful benefit in multi-drive rack deployments where aggregate heat and power consumption matter.
With sustained sequential transfer rates up to 261 MB/s, the Exos X18 12TB delivers throughput well above what most consumer NAS drives achieve under real-world sustained loads. This performance is particularly valuable for large sequential workloads — bulk data ingest, video surveillance recording, media archiving, and backup operations — where sustained throughput directly determines how long jobs take to complete. The 256MB multi-tier cache further supports consistent performance across both read-heavy and write-heavy workload profiles.
The Exos X18 is rated to a 2.5 million hour mean time between failures (MTBF) and 550TB of annual workload capacity — roughly ten times the workload ceiling of typical consumer NAS drives. This means the drive is engineered to sustain continuous read/write cycles around the clock without the accelerated degradation that affects consumer-grade drives pressed into enterprise roles. Therefore, it remains a reliable foundation even in storage systems that operate continuously without downtime.
The Exos X18 includes RAID-specific Error Recovery Control (ERC/TLER), which prevents RAID controllers from dropping the drive during extended read/write error recovery operations. Consumer drives without this feature are frequently ejected from RAID arrays during recovery, causing false drive failures and unnecessary rebuilds. Additionally, rotational vibration (RV) sensors compensate for vibration caused by adjacent drives spinning simultaneously in densely populated NAS enclosures, maintaining data integrity and consistent performance.
The ST12000NM000J ships in 512E (512-byte emulation) format, providing compatibility with legacy operating systems and RAID controllers while supporting modern infrastructure. Seagate's FastFormat capability allows the drive to be reformatted to 4Kn (4K native) sector size in the field where required, without data loss — giving administrators flexibility to deploy this drive across mixed-generation storage environments without sector size conflicts.
Seagate's PowerChoice and PowerBalance technologies allow the Exos X18 to intelligently manage power consumption based on activity levels. PowerChoice enables configurable low-power idle states that reduce energy draw during quiet periods, while PowerBalance lets administrators optimise the drive's balance between performance and power usage. In large-scale deployments where multiple drives operate simultaneously, these features translate into meaningful reductions in overall power consumption and thermal output.
What Does Recertified Mean?
Recertified drives are professionally inspected and tested units that have been returned, refurbished to a working standard, and verified for performance before resale. They provide a cost-effective route to enterprise-class storage capacity and reliability.
There are important differences to understand before purchasing a recertified drive. Please read the following carefully.
Professionally Tested
Each unit is inspected and tested to confirm operational performance before despatch
1-Year PCBoost Warranty
Covered by a 1-year PCBoost warranty only. No manufacturer warranty applies to recertified units
Cosmetic Marks Possible
Recertified units may show minor cosmetic wear. Functional performance is verified prior to sale
Enterprise Value
Access enterprise-class capacity and reliability at a substantially lower cost than new
NAS and Server Compatibility
The Exos X18 12TB is compatible with a wide range of NAS platforms, server systems, and direct-attached storage enclosures that accept 3.5" SATA drives. Always verify your NAS vendor's compatibility list before installation, as some enclosures may require a firmware update to recognise high-capacity drives above a given threshold.
Technical Specifications
| Feature | Specification |
|---|---|
| Model Number | ST12000NM000J |
| Product Series | Seagate Exos X18 |
| Condition | Recertified – 1-year PCBoost warranty |
| Capacity | 12TB |
| Interface | SATA 6Gb/s |
| Form Factor | 3.5 inch |
| Rotational Speed | 7,200 RPM |
| Sustained Transfer Rate | Up to 261 MB/s |
| Cache (Multi-Tier) | 256MB |
| Sector Size | 512E / 4Kn (FastFormat) |
| Drive Fill | Helium sealed |
| MTBF | 2,500,000 hours |
| Annual Workload Rating | 550TB per year |
| Load / Unload Cycles | 600,000 |
| Idle Power (typical) | Approx. 4.5W (idle A) |
| Operating Temperature | 5°C to 60°C |
| Dimensions (W x H x D) | 101.6 x 26.1 x 147.0 mm |
| Weight | Approx. 650g |
| Rotational Vibration Sensor | Yes |
| RAID Error Recovery (ERC/TLER) | Yes |
| Warranty | 1-year PCBoost warranty (recertified unit) |
Ideal Applications for the Exos X18 12TB
Multi-Bay NAS Storage Builds
In a 4-bay NAS populated with four Exos X18 12TB drives, a RAID 5 configuration yields approximately 36TB of protected usable storage — a substantial working volume for a small business file server, media archive, or home lab. Moreover, the RAID ERC/TLER support and RV sensors ensure the drives function reliably together in multi-drive configurations without the stability issues that affect consumer-grade drives in the same role.
Continuous Surveillance and Security Recording
Multi-camera IP surveillance systems generate sustained, continuous write workloads that quickly degrade drives not rated for this duty. The Exos X18's 550TB annual workload rating provides the headroom for high-bitrate, multi-stream recording without accelerating wear. Furthermore, 12TB of capacity delivers extended footage retention at professional bitrates — important for installations where storage of historical recordings is a compliance or operational requirement.
Backup Targets and Cold Storage Archives
As a backup target or long-term archive drive, the Exos X18 12TB combines the capacity needed to hold substantial backup sets with the enterprise reliability credentials required to trust it with irreplaceable data. Additionally, the lower cost of a recertified unit makes it easier to build redundant backup destinations — a sound strategy for any serious storage deployment where a single copy is not sufficient protection.
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Typical Warranty Periods (PC Parts & Computers)
| Product Category | Typical Warranty |
|---|---|
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