It doesn't quite match the largest capacity on the market for notebook-sized drives (its drives sport capacities from 120-250GB), but Seagate's Momentus 5400.4 range offers plenty of advanced features and, best of all, a five-year warranty should anything go wrong.

At 250GB, the ST9250827AS is the largest-capacity model in the Momentus 5400.4 range; it consists of two internal platters, each of which can hold 125GB, using perpendicular recoding technology. The formatted capacity of the 250GB drive is 232GB and with a retail price of around $236, this results in a cost per formatted gigabyte of around $1.

It's a Serial ATA-based drive, with a 3Gbps interface, and it also includes NCQ (native command queuing), which is something that some other notebook drives, such as Western Digital's Scorpio (WD3200BEVT), don't have. With a 5400rpm spin speed and an 8MB cache, the 250GB Momentus is also a decent performer.

In our write tests, the drive averaged 54.68MBps, and in our read tests it averaged 57.37MBps. While these are good results, they're not as fast as what the Western Digital scored. When copying data from one location on the Momentus to another, we recorded an average time of 20.87MBps, which Is actually faster than what the Western Digital achieved. This means that disk-intensive activities, such as file compression and de-compression, will be handled relatively swiftly.

Over a two-hour period of continuous transfers, the surface of the drive warmed up to 38 degrees, which is similar to what many desktop drives exhibit. That's not bad for a drive that's only 9mm thick and which spins 5400 times per second. It makes only slight ticking noises while it's performing vigorous seek operations, but, otherwise, it's a silent-running disk drive.

These operating traits, as well as its performance, make the Momentus a good option for a slimline or small-form-factor media centre PC. Assuming you can find ways to mount them securely, you could run two or more of these drives in a small PC, without having to worry about them overheating, making too much noise, or consuming too much power.

In our power measurement, the drive's peak consumption was 3.35W, which is slightly higher then the 2.9W that Seagate touts. This measurement was taken while the drive was copying data from one folder to another, so it's definitely a worst-case scenario. While idle, the drive will consume 0.9W.

Of course, the Momentus 5400.4 250GB is also a good upgrade or replacement option for a Serial ATA-based notebook, and it can also be used in a Serial ATA-based 2.5in enclosure as a portable, external hard drive. In the latter scenario, the drive can run off one powered USB port, negating the need for a separate power supply.

The biggest plus though, is the five-year warranty. While it doesn't mean you can forego backing up your data for five years, it means that Seagate will replace the drive should it fail within that period of time. Of course, if you don't have a backup of your data when it fails, then this will be a small consolation.