SSD or hard drive: which is best?

5 Jul 2013

Is it time to switch to an SSD or a new HDD?

When we benchmark PCs and laptops, we usually find that a high-speed SSD makes little difference to a system’s overall score. That’s because reading and writing files represents only a small proportion of the work involved in most computing tasks. The fastest disk in the world won’t magically let you finish a day’s work by lunchtime.

Yet, if you regularly need to shift large amounts of data back and forth, an SSD can save a significant amount of time. And if you use a fast SSD as your system disk, then you’ll notice an increase in responsiveness; programs and documents will open almost instantly, and your PC will start up and shut down more smoothly. Although the actual time-saving may be small, an SSD can give your PC a perceptible spring in its step.

To quantify this effect, we tried various tasks using a selection of drives. We started with a Western Digital Caviar Green desktop disk – a mechanical drive optimised for power savings.

The manufacturer doesn’t publicly advertise the speed at which this drive’s platters spin, but we suspect it’s 5,400rpm, fairly slow by industry standards.

We say that because even though this disk has a rather generous 16MB cache of fast onboard memory, it took 1min 21secs to shut down and restart our Windows 8 test system with this disk, and almost five minutes to copy a folder containing 5GB of data files. Opening a 1GB set of files in Photoshop took 23 seconds, and loading a level of Crysis took an agonising 49 seconds.

Faster disks

It was a similar story with Western Digital’s 1TB Scorpio Blue laptop drive. This model spins at an industry-standard 5,400rpm, and the synthetic CrystalDiskMark test found that it supports much higher raw transfer rates than the Green model.

However, its smaller 8MB cache is a liability in real-world use, leading to results barely any faster than the Caviar Green in our Windows, Photoshop and Crysis tests. Only when it came to copying large files did we see a significant benefit.

Next, we tested a 1.5TB Seagate Barracuda drive, with a fast spindle speed of 7,200rpm and a generous 32MB cache. This cut our reboot time to below a minute, and enabled us to load Crysis in 38 seconds. Photoshop and file-copy scores improved too. These results are about as good as you can expect to see from a mechanical disk: while Windows wasn’t exactly snappy, it certainly didn’t feel sluggish.

If you crave yet higher performance, one option is to choose a hybrid disk, which combines a high-capacity mechanical drive with a smaller quantity of SSD-type flash memory – effectively using the SSD as a high-speed cache to accelerate disk operations.

We tested the 750GB Seagate Momentus XT, which combines a 7,200rpm disk with 4GB of SSD storage, and were impressed by the results: Windows’ reboot time fell to 42 seconds, and our 5GB file-copy operation completed in 2mins 28secs – representing approximately double the performance of the Caviar Green drive.

The SSD advantage

For the ultimate in performance, there’s no substitute for a real SSD. Equipping our test PC with Samsung’s SSD 840 Pro gave all of our tests a huge boost. Windows 8 rebooted in only 23 seconds, and the 5GB file-copy test completed in a lightning-fast 34 seconds – around a fifth as long as the hybrid drive took. Crysis loaded in a swift 22 seconds too: in a multiplayer game, that could give you a real advantage over other players.

SSDs are undeniably expensive. The 256GB model of our Samsung drive currently sells for around £185 inc VAT, while the Western Digital Caviar Green offers around twice the storage for only £45. But if you want the most responsive PC you can get, an SSD can make a huge difference to the speed at which you can open, access and switch between applications.

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