Hard disks

Hard disks keep becoming larger, but bigger isn't always better. We put 32 drives, with capacities from 80GB to 1TB, through our rigorous benchmarking mill, as one storage size doesn't fit all.

The hard disk business has settled down after its huge leap forward in 2006, thanks to the introduction of perpendicular recording technology. Just when the detractors of this 50-year-old technology thought it was on its last gasp, hard disks once again have a rosy future. Even if solid state disks (SSDs) are starting to look viable for some desktop applications, they still can't come close to the capacity or price of a hard disk. Currently, the largest drives are a whopping 1TB in size, and the best-value drives come in at just 14p per gigabyte - no SSD can compete with that just yet.

This month, we gathered a whopping selection of 32 disks to help you choose your next upgrade. Capacities range from entry-level 80GB models to the latest 1TB monsters. In the same way as a range of cars is usually offered with various engine sizes, hard disks from the same family often have different specifications under the hood. They can have different buffer sizes, as well as radically different areal densities. These factors can have a major effect on performance, power consumption, noise levels and price.

For each manufacturer, we've included a number of different-capacity drives from the same range. Whether you need a storage behemoth for your burgeoning video collection, or just a fast-boot disk, you'll find the right drive for your requirements. Read on to find your perfect platter.

Our tests can be split into two categories: synthetic and real-world. Before installing Windows, we hooked up each disk to our test PC and ran Simpli Software's HD Tach 3.0.1.0 RW (www.simplisoftware.com) on the unformatted partition. This performs a series of read and write tests across the entire capacity of the disk. Not only does HD Tach provide an assessment of average access times, but it also reveals the sustained read and write speeds. As well as the overall average throughput, HD Tach records throughput across each sector of the disk. This allows us to calculate the transfer rates for the inner and outer edges of the platters, corresponding to the slowest and fastest portions of the drive.

However, how a disk performs in real applications is of greater importance. We also ran a couple of tests designed to illustrate how well each disk would cope with the kinds of tasks you're likely to perform every day. First, we ran the Gimp image editing section from our Media Benchmarks. This entails editing a lot of high-resolution photos, so it requires good access times as well as fast throughput. Our second real-world test involved loading the Relic level from Crytek's texture-intensive Crysis. Again, this requires good access times and fast throughput. We recorded the time it took to load the level three times, rebooting between each and calculating the average.

The tests were executed on a PC based around an Intel Core 2 Duo E6750 processor allied with 2GB of Corsair Dominator DDR3 RAM. These were installed on an MSI X38 Diamond motherboard with an ATI Radeon X1950 XTX graphics card. We used the 32-bit version of Windows Vista Ultimate as our operating system for the real-world tests.

Performance isn't everything, however. Value is also important, and with a hard disk, much of this revolves around how many gigabytes you get for your money. We found the best available price for each drive, and divided this by the usable capacity when formatted as an NTFS partition to get a price per GB. The cheapest drives aren't necessarily the best value for money either. For the value score, we took into account features such as power consumption and noise levels. The hard disk may not be the biggest contributor to either of these in a PC, but in an HTPC or a system with lots of drives, they could be significant.

We arranged our reviews by capacity, so you can choose the best drive for your storage requirements. However, there's a fair amount of variation in price, and spending a few extra pounds could help you leap to the next category. Therefore, we've also noted where a particular drive is a false economy, or so much better value than the drive in a lower category that you're better off spending a little more cash on a larger drive.