Toshiba mk1234gax

Click on the picture to see a closer image of each hard disk. The Toshiba disk is marked with the number 4.

While you can usually expand your desktop PC's storage space by adding a second hard disk, notebooks offer two big obstacles: there's almost certainly only room for one disk inside the chassis, and transferring the data is a pain. You'll have to either back up your files to a CD or DVD, or buy an external 2.5in hard disk caddy (we test six next month) and then fit your old hard disk inside. You then just transfer your data when you've installed Windows on your new disk.

But the effort is undoubtedly worth it. The biggest benefit of upgrading your hard disk is greater capacity, but you should also notice a speed boost. You'll see from the results on the feature table that the new hard disks offer similar levels of performance, but we also tested a four-year-old hard disk for comparison: in disk-intensive tasks, such as our Photoshop benchmark, the new disks were 15 to 20% faster. And although a 20% boost may not sound much, it could be the difference between a smooth-running machine and a jerky one.

Performance matters

There are three main factors that influence the speed of a hard disk: its areal density, the amount of memory buffer and its rpm - the number of times the platters revolve per minute. But this is all theoretical: what we really care about are the speeds the hard disks achieve in our tests. Following our usual real-world methodology, we use a notebook as our testbed. It uses a 1.66GHz Intel Core Duo T2300 with 512MB of 667MHz DDR2 memory.

Our first set of tests is for sustained transfer rates (using HD Tach RW, www.simplisoftware.com). The 7,200rpm disk was quicker than the rest, but to see this effect in real life you'll have to be reading from a large file that was written contiguously on the disk (that is, the individual bits of data that make up the file lying sequentially next to each other).

A more practical test is for read-and-write speeds, and we test using both small and large files. The full results are on the feature table. We also run our full suite of application benchmarks, but there proved to be little variation: all the new disks scored 0.77 overall, compared to 0.74 for the four-year-old disk.

But this doesn't mean you won't see a difference in real-world use. To demonstrate this, we focus on the Photoshop test that's part of the PC Pro benchmarks. This is hard disk intensive, as it involves holding more than 30 high-resolution photographs in memory at one time, causing the notebook to frequently call on the page file.

Reviews

Toshiba is one of the leading names when it comes to hard disks, with its 0.85in drives powering many consumer electronic devices. On this occasion, however, its 2.5in offering - the Toshiba MK1234GAX - failed to stand out from the crowd. Not only did it take the longest time to complete our Photoshop benchmark, it also came bottom in the more theoretical sustained transfer rate test. Even though it clambered its way to mid-table in our read-and-write tests, this drive is only worth considering if you can find it for £80 or less.

The Fujitsu MHV2120AH is immediately more appealing due to its price and its availability. Sold through such mainstream outlets as PC World and costing a reasonable £97 exc VAT, few people will be disappointed if they need to buy a drive in a hurry. However, it proved to be an unexceptional performer: only the Toshiba was slower at completing our Photoshop benchmark, and the Fujitsu's read speeds were among the slowest here.