Say you’ve decided to buy an SSD, there are some factors to consider when buying an SSD besides the price and speed of the chips themselves:
- SSD capacity impact on performance. Higher capacity SSDs have higher theoretical performance due to the nature of the SSD way of work. Since the data is written to the NAND (the flash memory) concurrently, more working space lets the control ler of the SSD write more data concurrently resulting in a higher data rates. If you’ll compare the specifications of 64GB, 128GB and 256GB drives of the same series, you’ll see that the higher the capacity, the better the performance specs. The benchmarks confirm it – in this Intel 330 60GB, 120GB and 180GB review you can see that the write speed is heavily impacted by going from 120GB drive to 60GB, for example. However, note that these are synthetic benchmarks. In practice, for the casual user, it doesn’t matter – you won’t feel the difference unless you’re running a heavy duty server or transferring large files all day, you don’t have to worry. Anandtech themselves (from the review above) use the 120GB Intels 520 for time now for their heavy duty server, so it should really not be a problem for the casual user.
- SSD capacity impact on the SSD health. The SSD memory is a NAND flash memory which wears out the more writes are made to it. Now, with several degrees of effectiveness, the SSD drive controller knows how to spread the writes all over the NAND memory cells so that no specific cells will ‘die’ sooner than necessary. Now, it’s not really a concern if you don’t using the SSD really heavily and you’ll get your years of good performance, but still.
- TRIM performance. TRIM is a process that is meant to deal with the performance degradation of an SSD over time due to its work mechanism. The SSD performance gets lower with use, especially heavy use, with differentiation over the SSD model. You can read more about it here. Moreover, TRIM is not perfect and the performance in some drives are considerably lower after being used heavily, even if you use TRIM. In order to get highest performance from your SSD again, you’ll need to use secure erase.
- Power consumtion – for a desktop user it doesn’t matter, but for a laptop user, another 1W when idling can reduce make a difference, if she wants to squeeze as many hours as possible.
- Performance in specific scenarios. Some of the top SSDs are less impressive when dealing with incompressible data (like video files, photos and things like that), especially SSDs that are based on the Sand-Force controller which rely on compression of the data to be more efficient (need to read less data). If that’s what you are doing with this SSD, you should take that into account. For example, the Kingston SSDs become less attractive compared to similarly priced SSDs in this case.
- Sometimes it takes time for new SSDs to get into shape. Sometimes new SSDs also come with new controllers, NAND, new firmware logic or combination of all these and it is often not perfect as it can right away. Firmwares get updated and improved (like in the Vertex 4 case), prices change to be more competitive and the picture get clearer. For example, the new Plextor M5 SSDs use new controllers and NANDs and it seems there is much room for change as currently they do not offer an additional value over the old Plextor M3 SSDs. So, sometimes it is better to wait several months, if you can allow it.