Solid State Drives (SSDs) do the same job as hard drives (except much faster), but they shouldn’t be treated exactly the same

SSDThere is no doubt that the performance boost offered by SSDs is huge. As far as the content of our drives is concerned (and that includes the operating system, the programs, and the data), we can just enjoy the speed boost and carry on much as we did before.

But the whole technology underlying SSDs is different to hard drives. They are more akin to USB pen drives (“memory sticks”) than hard drives, and this means that there are some things we should take into account.


Do not defragment a SSD. The way that data is stored on them is different to hard drives, so defragmentation won’t help. Worse than that, SSDs only have a finite number of read/write operations before they pack up (don’t worry – a SSD is likely to last longer than the computer it is inside, and longer than a hard drive). Defragmenting a SSD would just needlessly “use up” loads of the available read/write cycles. Modern versions of Windows recognise if you have a SSD installed and don’t attempt to defrag it in the old way. Yes, there is some “disc housekeeping” that Windows performs monthly on SSDs, but we don’t need to worry about it. If that sounds patronising and you’d like to know more about it, then I recommend this article on SSDs by Scott Hanselman. The long and the short of it is – don’t run utilities like Defraggler on a SSD.

Wiping a SSD

Road RunnerOn a hard drive, files are not actually removed when you delete them. They are just marked as “available for over-writing” and the system takes care of overwriting them with new data as and when it feels like it. This means that it is sometimes possible to recover information from a drive that you thought had gone to data heaven. So, there are utilities available (such as Ccleaner’s Drive Wiper) that deliberately overwrite deleted files with meaningless stuff so that the underlying deleted data can not be recovered. SSDs do not work in the same way. When something is deleted then it is deleted from the SSD immediately. Do not attempt to “wipe” deleted data from a SSD.

Operating System

Don’t use a SSD under Windows XP or Windows Vista. It’s not very likely that you would want to do this anyway, but don’t. These old operating systems are not capable of sending the instruction to the SSD (called “trim”) that deletes data in an efficient way. This would eventually mean that the performance of the SSD is badly compromised as redundant data is deleted in an inefficient manner to make way for new data.

Filling It Up

On hard drives, a rule of thumb is that you should never let the drive get more than 90% full as its efficiency will start plunging from that point on. This is because the drive and operating system have to work harder and harder to find somewhere to record (write) new stuff. Something similar happens with SSDs, but here the rule of thumb is not to let the drive get more than 75% full. For some in-depth information on this see Anand Lal Shimpi’s article on filling a SSD.

Speedy GonzalesA Waste of Space

Unless you can get absolutely everything you need on your SSD (and that means Windows, your programs, and all of your data), then don’t waste your SSD by storing large files of infrequently used data on it. Your music files and your videos will not run any more efficiently by being stored on a SSD. Indeed, on my Mac Mini, I have the operating system and programs on a small (120gb) SSD and my entire musc library is stored on a 1tb external drive connected by USB2 (not even USB3). This works perfectly well. OK, it probably means that when I open iTunes my music is not displayed for a fraction of a second, but thereafter it runs just as well as if the drive were an internal hard drive or a SSD.

The same argument might not apply to your photos collection – especially if you do a lot of editing of your photos, or if you often “leaf through” a large number of pictures. There’s no hard and fast rule here, but I would certainly keep anything off the SSD that would push the available free capacity of the SSD down towards the 25% mentioned above (see “Filling it Up”).

SSDs are a big advance on hard drives. No doubt they will eventually be as large as – and then larger than – current hard drives at the same price or cheaper. In the meantime, it’s not surprising that there are some small adjustments needed in our thinking and our practice when using the current generation.

© 2011-2015 David Leonard
Computer Support in London
Privacy Policy Suffusion theme by Sayontan Sinha