Choosing an SSD

Solid State Disks – They are a direct replacement for spinning disks right? Well the answer is “yes” but there are more factors to choose. Of course the 1st factor is space. SSD drives are up to 512GB (on a normal 2.5inch drive format – June 2011). Of course this is smaller than the spinning disk market of today. So if you have a laptop with a single spinning disk and it’s size is 1TB (approx 1000GB) and you have used more than 400GB of it – you will need to do some shuffling and will need some decision making.

Many people will store music, videos, photos on their system drives. While, this does offer ease of use and availability of all of your files, it requires you to have a large disk. It also is not particularly secure. Hardware failure, or theft of a laptop can cause loss of data, and those wedding photos/Christening/stag night photos that we all hold so dear will be lost.

You always regret not backing these files up.

With today’s online offerings aplenty – there are hundreds of sites that offer to store all of this data on their systems. They all sit in managed air conditioned server rooms, with clustered, reliable and backed up servers. Many are free – some you pay a small amount per year or month to store your data for you. This way if you lose your laptop through failure or theft or accidental damage, your data is all safe.

Of course even this is not 100% reliable, but is a lot safer to store your treasured media up in the Cloud.

With fast internet now available to almost everyone – we all should be doing this as a matter of course.

Using this method of storage allows you to choose a smaller and cheaper Solid State Drive for your laptop. Also forces you to upload your data to a Web repository as you will run out of space.

I’d always recommend installing your new SSD into a system and then loading a fresh install of the OS, rather than copying the disk across. Though there may be instances where this is not an option so there is always the Hard Drive Copy Station Which should simplify this process.

So which SSD do you choose? Spinning disks are measure by their rotation speed. Laptop drives spin at 4200 rpm, 5400 rpm or 7200 rpm. The faster it spins the faster you can read the data. Most systems now have a SATA II interface or the old PATA (or IDE) 44pin interface.

IDE has a max throughput through the interface of 100 MB/s.
SATA II has a max throughput through the interface of 3GB/s

Looking at HD Tach Benchmark results
The Average Read speed of a typical 5400rpm IDE drive (e.g. Maxtor DiamondMax D540X) is 28.3MB/s
The Average Read speed of a typical 7200rpm IDE drive (e.g. Maxtor DiamondMax D740X) is 35.9MB/s

The Average Read speed of a typical 7200rpm SATA II drive (e.g. Maxtor MaXLine Plus II) is 49.9MB/s

Most Solid State Disks of the last generation are achieving 280MB/s Average Read Speeds.

SATA 3 ups the interface capability up to 6GB/s and the latest spec SSD’s claim 500+ MB/s read speeds.

What does this mean to the performance of my PC? If you compare the figures – the Average Read speeds are multplied by a factor of 10. Your PC will boot in a matter of seconds – you will be able to use it immediately. Open multiple programs all instantly.This will change the world of computing.

OS Choice – Some of the latest SSDs support what is called TRIM. The latest Operating Systems support the TRIM command (Windows Server 2008 R2, Windows 7, FreeBSD, Linux kernel 2.6.33, Mac OS 10.7 Lion,OpenSolaris) – check out WIKI’s TRIM Command article for more on this.

TRIM effectively keeps your drive optimized and prolongs it’s lifespan. This is important as there is no need to defragment an SSD drive. Without this function, however, there is manual TRIM functions available to you – but built-in TRIM is, of course far better.

Remember – all of the manufacturers use basically the same NAND Flash and program the controller chip (Sandforce, EastWho, Indilinx etc). They then publish the results that show their drive in the best light. It’s a bit like a car manufacturer who installs a Ford Zetec engine – they bought the same engine from Ford that is used in the Ford Focus. They believe that acceleration to 60 is more important than top speed – so tweak the gearbox to give good acceleration. They publish the 0-60 times – but omit the top speed. Ford may publish both figures – the 0-60 will be slower – but they have a top speed. It’s up to you to decide which is better for your needs.

SSD manufacturers do the same thing. Things to look for:

Random Read/Write speeds
Sequential Read/Write speeds
(the above at 4kb blocks and smaller)
Input Output Per Second – IOPS – basically means concurrent Read and Writes (web server is a good example of a need for high IOPS where multiple people accessing a site will be requesting Reads all at the same time.
Mean Time Before Failure (MTBF) – though most are consistent on this.
TRIM Support – Yes or No

If they publish it – they are proud of it’s performance in comparison to the competition. If they do not publish it – it’s nothing to shout about.

There is a lot more about the whole way an SSD works – and the choice to the user is much larger than previous spinning disk technology – hopefully this helps you in choosing the correct disk for your needs.

We welcome feedback on this and look forward to ongoing discussions.

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