Seagate Momentus 7200.4 (ST9500420AS) hard drive

The Seagate Momentus 7200.4 (ST9500420AS) is a 500GB 2.5in hard drive with a spin speed of 7200rpm and a 16MB cache. Despite being small enough to fit in a laptop drive bay it is faster than many 3.5in hard drives designed for desktop PCs.

The Seagate Momentus 7200.4 is faster than 5400rpm laptop drives we've tested, such as the Western Digital Scorpio Blue (WD5000BEVT) and the Seagate Momentus 5400.4 250GB (ST9250827AS). This was shown in our transfer tests.

We copied 19.4GB of files from our testbed PC, which uses a Western Digital Velociraptor (WD3000GLFS), and recorded a write speed of 77.2 megabytes per second and a read speed of 85.99MBps. Duplicating data on the Momentus hard drive (copying data from one folder on the drive to another), was achieved at a rate of 25.63MBps. This is an excellent result, especially given that many desktop hard drives such as the Hitachi Deskstar 7K1000.B (HDT721010SLA360) and the Seagate Barracuda 7200.11 1.5TB aren't as fast.

Out in the open, the Seagate Momentus 7200.4 ran at an average temperature of 30 degrees Celsius. This is nine degrees cooler than a typical 3.5in hard drive. Because it's as fast as a desktop drive and has such a large capacity, it's a good hard drive to use in a PC case in which space is at a premium (such as a media centre). The relatively low heat production means you can use a couple of these drives in a RAID array in a cramped case without worrying about them overheating.

As well as delivering faster performance, the higher spin speed results in a higher level of vibration. When we installed the Seagate Momentus 7200.4 (ST9500420AS) hard drive in a 15.4in laptop, its level of vibration was more noticeable through the palm rest than it was when we installed a 5400rpm Western Digital Scorpio (WD3200BEVT).

The Seagate Momentus 7200.4 (ST9500420AS) has a formatted capacity of 465GB and a cost per gigabyte of 47 cents. While this is expensive when compared to desktop hard drives such as the Hitachi Deskstar 7K1000.B (HDT721010SLA360), which has a cost per formatted gigabyte of 26.7 cents, it is competitive for a notebook drive. It is slightly cheaper than the 55.7 cents per formatted gigabyte of the Western Digital Scorpio Blue (WD5000BEVT).

The Seagate Momentus 7200.4 (ST9500420AS) will be useful if you're after a high-performance laptop hard drive for tasks like video editing or playing games. It's also worth a look if you're building a fast and cool media centre for your home entertainment system.