What's the best SSD: Buying advice
Solid-state is standard-issue for storing your data in tablets and smartphones, where it’s relied upon for its tiny size and knock-proof nature. The same assets are handy in desktop and especially laptop PCs, but more traditional computers can also unlock SSDs’ perhaps most prized virtue – their speed.
Instead of a fragile magnetised disk whirring at 90 or 120 times every second, SSDs store binary data in shock-resistant silicon chips. And besides being physically robust, silent, smaller and lighter than any hard-disk drive, the big incentive to opt for a flash drive remains performance. Data can be read and written hundreds of times faster from electronic non-volatile flash cells.
This speed factor is about so much more than go-faster bragging rights though. Old-school desktop computers may still battle it out over who has the fastest processor or the hottest graphics card, but SSD performance is all about the user experience – applications launch in almost no time, web pages spawn faster and files copy in a fraction of the time.
Put simply, and regardless of whether your processor has 3, 5 or 7 after the ‘i’, the whole computer just responds so much better to your touch. The only real drawback has been the exortionate price of entry to the premier-class storage club.
Until now maybe. It’s taken six years or more, but we are now at the state where the solid-state drive, the SSD, is a truly affordable component for any computer user. And if your wallet won’t even stretch to £100, just juggle your storage budget instead and get a 256GB drive.
Performance has swelled over the years – not just in the drag-race test of copying big files, but crucially with the way that small files can transfer. Much of the background housekeeping of a modern operating system is with the continual reading and writing of very small files of 4kB or smaller. It’s the random access of these all over the platters that can choke older disks that need to physically move a pickup head across spinning platters.
We’ve reached a point where just about any SSD you put into a computer to replace a hard disk will transform your experience. For performance seekers, there’s still a case for finding the fastest. And that fastest metric is still as much about small-file transfers, which we can measure by the number of input and output operations capable in one second – otherwise known as IOPS. The best SATA flash drives are currently returning figures around 100,000 IOPS, made possible by the way that datastreams can be paralleled together, a major asset of flash over disks.
Performance – in terms of the speed with which data can be read and written – has now effectively plateaued among the best SSDs. It’s not that flash memory has reached its limit, far from it, but the Serial ATA interface between the flash and your computer is now the bottleneck.
Until the next-generation of data interface is ratified, most PCs still use SATA Revision 3 with its 6Gb/s nominal speed, and circa-550MB/s real-world ceiling. Nevertheless, some are forging ahead with alternatives, notably Apple with its adoption of direct PCIe-connected flash drives in its Macs. This busts the old SATA limit to allow speeds of 700MB/s and more on even its cheapest MacBook Air.
Despite current SATA SSDs’ shortcomings, we still test the essential speed, both in large-file sequential transfers and small-file random access, as differences do exist between brands and models.
When buying an SSD, look out for long warranties and high data-write limits if you prize data integrity, although with the help of proper backup routines, data loss is less an issue today. Some SSDs demand more power than others, and where this is known we’d advise against fitting in a laptop if you value your time away from the mains. Also look out for manufacturers that provide accessible support with firmware updates possible on the platform of your choice. Most storage brands are still routed in the Wintel world and don’t make it easy to apply maintenance patches on their drives unless you run Windows.
What's the best SSD: How we test
Each SSD was benchtested on a desktop PC kindly loaned by Chillblast, based on an Asus Z87-A motherboard with Intel Core i7-4770K and 8GB RAM, running Microsoft Windows 7 Home Premium SP1 64-bit. We assessed most aspects of a drive’s performance with industry-standard benchmark tests for Windows, namely ATTO Disk Benchmark, HD Tune Pro, HD Tach, CrystalDiskMark and AS SSD.
Measured speeds for storage products are typically in megabytes per second (MB/s) for large files; and input/output operations per second (IOPS) for paralleled small-file transfers.
What's the best SSD: Conclusion
Sometimes group tests of related products elicit one or two clear winners, making these the natural choice in terms of value or performance. This isn’t one of those tests.
In terms of performance, any SSD here will transform a disk-based PC. They will all merrily let you read the entire contents of a 25GB Blu-ray film in less than a minute. They should all allow even Photoshop to launch in just a few seconds. The deciding factors are increasingly now about longevity and price.
Solid-state flash cells will age and wear out, but limited lifespan is a reality of hard disk drives, too, and after some serious concerns in flash technology’s early days, we can be reasonably certain that even with very heavy use, the typical user – even a professional designer, for instance – is unlikely to wear out an SSD inside five years.
Most people are conscious of cost and won’t spend more than is logically necessary, so on that basis, we must point to the best value drives in this group, namely the Seagate 600 and Crucial M550. At the time of writing, these were both priced around 40p per gigabyte, a most attractive offer – especially when compared to the £2 per gigabyte figures of just a couple of years ago.
For the best performance, the Crucial M550 also stands up well, along with the Intel 730 and OCZ Vector 150. Special mention must also go to two drives not in this group, the Samsung 840 Pro and 840 EVO (tinyurl.com/l5edqoy), which offer superb performance at competitive prices. With prices fluctuating weekly, it pays to shop around. By the time you read this group test, this already tempting upgrade may have hit the 30p per gigabyte level.