Are SSDs reliable enough for work laptops?

A recurring theme in readers’ emails over the past few months has been the SSD, or solid state drive.

Readers are asking me whether SSDs are now reliable enough for day-to-day use in a business laptop. Do they still wear out? What are their benefits? Should I get one in my new laptop? Should I upgrade my old laptop to SSD?

I’m a great fan of using SSDs in small laptops – actually, in all laptops, although they’re especially suited to smaller machines – but before I explain why, let’s take a quick step back.

I’m a great fan of using SSDs in small laptops

SSDs have been around for well over a decade in various forms, and some of us will have first seen them as smallish drives that plugged into a PC Card slot (or PCMCIA as it was known back them).

Although they appeared as drives on the laptop, such devices were really the precursors of today’s USB memory sticks, rather than real replacements for internal hard drives – it wasn’t until 2007 that mass-market laptops started shipping with SSDs replacing the traditional hard drive as their main storage.

Lifespan

Things really took off that same year with the launch of the Asus Eee PC 701, the original SSD-based netbook. These days, there’s a whole slew of SSDs available from various vendors, and various models have been examined in PC Pro’s reviews and Labs tests over the past few years.

Many people worry about SSD reliability, and rightly so, because there were all kinds of problems with early SSDs going bad after a year or so of use.

The drives are built using NAND-based flash memory, and these silicon devices have a finite lifespan: for a typical multi-level cell-based (MLC) SSD, each NAND cell can be rewritten only about 10,000 times before it becomes unreliable.

Obviously, in a typical PC environment where files are being shuffled around all the time in the background, and page files and content indexes constantly updated and rewritten, 10,000 writes isn’t going to last long at all.

Worse still, individual data bits aren’t addressed directly – instead, as with a traditional hard drive, data is written in chunks called “pages” and each page might contain data from several files. Even these pages aren’t addressed directly but grouped together into blocks, so a small change to one file means the whole block must be rewritten.

More reliable

That said, any drive manufactured in the past couple of years will have very good “wear levelling” algorithms in its controller firmware that keep track of how many times the various cells within the drive have been erased, and shuffle data around to spread the wear evenly.

Any drive manufactured in the past couple of years will have very good ‘wear levelling’ algorithms in its controller firmware

As a result, a modern SSD is an extremely reliable bit of kit, and as long as you take sensible precautions – such as switching off automatic defragmentation (Windows 7 does this automatically whenever it detects an SSD) – the drive should last for the lifetime of your PC. I really don’t think you should be overly concerned about your SSD wearing out, especially if it was manufactured within the past year or two.

There are several advantages to SSDs, along with a few disadvantages. The main benefit is speed – I’ll come to that in a while – but speed is also a potential disadvantage: because of the way in which they work, SSDs run slower as they fill up with data.

As with the wear issue, this is a “not as bad as it used to be” problem, because modern controllers and operating systems work together to minimise it. In particular, where both drive and OS support a command called TRIM (and yes, it’s written in capitals despite being neither an acronym nor initialism), the long-term performance issues are greatly reduced.