Seagate
Seagate Momentus 5400.2 ST9120821AS 120GB 5400 RPM 8MB SATA 1.5Gb/s 2.5" laptop hard drive
A 120GB 2.5-inch laptop hard drive spinning at 5400 RPM with 8MB cache and a SATA 1.5Gb/s interface for low-power storage upgrades
- PackagingBare Drive
- InterfaceSATA 1.5Gb/s
- Capacity120GB
- Cache8MB
- Average Seek Time12.5ms
- Average Write Time14.5ms
- 120 GB capacity stores documents and media
- 5400 RPM spindle delivers responsive everyday performance
- 8 MB cache speeds up frequent file access
- SATA 1.5 Gb/s interface connects directly to laptop motherboards
- 2 W seek power extends battery runtime
Capacity and interface
The Seagate Momentus 5400.2 ST9120821AS is a 120GB 2.5-inch laptop internal hard drive with a SATA 1.5Gb/s interface. It spins at 5400 RPM and includes an 8MB cache. The drive is supplied new as a bare unit without cables or brackets.
Who this suits
This drive suits owners of older notebooks or external enclosures that require a SATA 1.5Gb/s 2.5-inch drive for a direct replacement or a modest capacity upgrade. Low power draw of 2.2W seek and 0.28W standby helps preserve battery life. Buyers who need more than 120GB of storage or a faster 6Gb/s SATA link should consider other options.
Deciding specification
The SATA 1.5Gb/s interface is the single specification that decides compatibility. The host system must provide a matching SATA 150 port; drives with a 3Gb/s or 6Gb/s interface will not operate at their rated speed on this connection.
Highlights
- 120 GB capacity stores documents and media
- 5400 RPM spindle delivers responsive everyday performance
- 8 MB cache speeds up frequent file access
- SATA 1.5 Gb/s interface connects directly to laptop motherboards
- 2 W seek power extends battery runtime
Specifications
| Brand | Seagate |
|---|---|
| Series | Momentus 5400.2 |
| Model | ST9120821AS |
| Packaging | Bare Drive |
| Interface | SATA 1.5Gb/s |
| Capacity | 120GB |
| Cache | 8MB |
| Average Seek Time | 12.5ms |
| Average Write Time | 14.5ms |
| Average Latency | 5.6ms |
| RPM | 5400 RPM |
| Features | Native Command Queuing Low power consumption for maximum battery life QuietStep ramp load technology for improved durability and inaudible load and unload acoustics Rugged mobility |
| Form Factor | 2.5" |
| Shipping weight | 0.36 kg |
| Package size | 152 × 102 × 51 mm |
Questions about this item
How can I confirm the drive is operating correctly after installation?
The drive should spin at 5400 RPM with an average seek time of 12.5 ms and average latency of 5.6 ms; the SATA 1.5Gb/s interface will report a 150 MB/s link speed in BIOS or OS tools.
What is included with the bare drive and what must I source separately?
Only the 2.5" ST9120821AS unit is supplied; you must provide a SATA data cable, a SATA power connection from the laptop or enclosure, and mounting screws or a caddy if required.
Which capacity from the Momentus 5400.2 line should I choose for a 120 GB requirement?
The ST9120821AS is the 120 GB model in the Momentus 5400.2 series, delivering 8 MB cache and 5400 RPM performance for that capacity.
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