The SSDs are one of the most interesting components to consider when buying a new computer or updating a current one. In the latter case, either by replacing the magnetic hard disk or by installing a SSD next to it.
The advantages of the SSD over conventional hard drives are diverse, but especially they provide a much higher performance in time access, speeding up OS startup, application opening and the transfer of data.
Since they are based on NAND flash memories, the lack of moving parts in a SSD provides advantages like being almost noiseless as also presenting very low heat emission and power consumption. The improvement on the latest generations made them robust and reliable, having an Mean Time Between Failures (MTBF) very similar to the one of a conventional hard disk.
The arrival of new formats even smaller than the classic ones connected to the SATA interface and the continuous price reduction the sector presents, has provided additional reasons to recommend the SSDs for data storage. Today we will go through the most important properties a user must know about these devices and we will update the buying guide with the units presenting the best performance/price ratio.
The most popular format is the one that presents the standard 2.5 inch size with a SATA interface (the same as laptop’s hard disks). Take note that they come with two different thickness of 9.5 and 7 mm. If you are going to mount it on a laptop you must verify that the SSD height of choice is supported by your computer. For desktop PCs you can choose anyone of them, if your PC case does not have a specific place to mount 2.5 inch drives there are adapters available to convert them to 3.5 inch.
Another important format to consider is the one called M.2, which is meant to replace the mSATA one. Its advantages are they compact size, lower weight and less power consumption over those based on the 2.5 inch standard. They also can provide a better performance depending on the interface as we will see later. As disadvantages, we can name they are more expensive and less compatible since many motherboards do not support them.
A third format we can find for desktop computers are the ones built as a PCIe board directly connected on a PCI express slot on the motherboard. In this format we find units which are a single board with the memory chips mounted on them or the ones which work as an adapter for M.2 units to use in motherboards without this specific connector.
Performance – Connection Buses
Another particular property to consider when buying an SSD is the connection bus. The 2.5 inch units are connected to the SATA interface (do not buy anything not supporting SATA III – 6 Gbps), while the M.2 ones can be connected to SATA or PCIe. The latter ones are the most extended and they really make a difference in performance.
The interface used is the main factor dominating the SSD performance. When you replace with one of them a conventional hard disk you will experience a significant boost of your laptop speed, especially in boot times, applications launching and file transfers.
However, using the same connection bus not all the SSDs offer the same performance, due to the memory chips used and especially their controller. The user who buys a SSD drive nowadays should ensure to get at least 500 Mbits on a SATA connection for read and write operations. There are very cheap SSDs providing much lower values than this especially for writing, try to avoid them.
The M.2 units using the PCIe interface are the fastest ones you will find among consumer options. They use the native PCI express connection to boost their performance to a theoretical maximum which can be up to 5x higher than SATA. Although initially their price was prohibitive for the general consumers, they are being reduced as compared to SATA units, and they seem promising as the future for PC storage.
It must be noted that the new generations of PCIe M.2 SSD support the NVM Express standard, designed from scratch to take advantage of the low latency and parallelism of the PCI Express bus. They offer spectacular performance and if the unit is made bootable the rest of the drives can be completely ignored.
If you are considering to buy these kind of SSDs to completely replace your hard drives, double check your motherboard supports or can be upgraded to handle the NVM protocol and to make this drive bootable. Otherwise, you will not be able to use it as the main unit for the OS.
There is a significant difference as how the data is handled by SSDs and HDDs. The SSD writes the data into chunks called pages. A group of pages is called a block and in order to write new data in a filled block, the entire block must be deleted before. When a page must be updated, all the information present in the block must be moved to a new one, the block is erased and then the contents of the updated page plus the previous block is written back.
This operation is almost instantaneous but requires free space on the drive to be performed properly. As a consequence, if there is not enough empty space the process becomes less efficient and the drive slows down. We mention this technical point because it affects the usable capacity of the SSDs. To ensure its maximum efficiency we should keep about 20 percent of the unit empty.
For this reason, we recommend the purchase of a unit with at least 250 GB for a laptop if we are replacing the installed hard disk. SSDs with capacities of 128 and 64 GB should be avoided unless the budget is critical.
On a desktop PC, if we replace all the HDDs the storage capacity are usually greater (expensive option but the most effective). A reasonable option is to use both a SSD as the first boot unit for OS and applications and a conventional hard disk for data storage.
Using a low capacity (and therefore cheap) SSD together with a HDD is a good option for saving money. If your budget is big you can go for a fully SSD build as the best option. Nowadays units with 1, 2 and 4 TB are already common. Fixstars has for sale models with 6 TB, SanDisk and Samsung are going to offer 8 TB units this year, and Intel by Micron is going to have 10 TB models.
Resistance and Longevity
Despite they consist of mechanical parts, conventional hard drives are still the “standard” in terms of resistance regarding devices for data storage, hence their massive use in servers and data centers working 24/7 where reliability is a must. In addition, these places require benchmarks and certifications which can last for months and therefore the entry of SSDs has been hitherto slight.
Unlike hard drives, SSDs do not have moving parts which makes them safe regarding mechanical failure. By contrast, SSDs are more sensitive to power fails while the drive is running, which can cause data corruption or even a total device failure. In addition, the memory blocks on an SSD have a limited number of write operations.
Fortunately, the new generations have improved greatly in reliability. All SSDs include additional free memory cells to avoid loosing capacity when others fail, relocating damaged sectors. Manufacturers offer nowadays 3, 5 or even 10 years of warranty and the official SSD lifetime is about 5 to 7 years.
Latest endurance tests have confirmed this increase in reliability with some units surviving massive write tests of over 2 petabytes. That is a huge amount of data, which for a normal user will take tens of years to reach.
For recent generations, manufacturers are choosing Triple-level cells NAND flash memory (TLC). This technology increases the storage density and reduces costs, but also decrease the resistance of previous technologies like MLC and especially SLC (Single-Layer Cell) that only stores one bit per cell and you will not find in the consumer market anymore.
Buying a SSD – Models and Prices
Taking into account all the previous information we are ready to go for SSD shopping. We can discuss a lot more about the controller used, the cache, the flash memory manufacturer and the fabrication process that we discussed in the previous paragraph, but that detailed information out of scope of this guide. It is enough to mention that any big manufacturer (Samsung, Kingston, OCZ (Toshiba), SanDisk (WD), Crucial …) will offer us interesting and varied models in performance and capacity.
Regarding their cost, we note that prices have risen (in average) compared to 2016. We had anticipated it: the increase in the demand for flash memories has been steady not only for SSDs, but also due to smartphones production and other devices. That made to stop a constant decreasing trend of the SSD pricing as the cost of NAND flash memory was lowering, the basic component and more expensive to produce for SSDs. Different analysts agree that prices will rise even further by the end of the year. We are always talking about the sector average, because actually some particular models have gone down in price.
If you are willing to buy, we offer you a selection of current solid state units with different capacities. We classified them by the formats we mentioned before, SATA and M.2-PCIe. There are many options from all the big manufacturers.
- Samsung EVO 850. This is the best selling model from the leader of the SSD sector. The 250 GB version is the most cost-effective per GB (108 dollars). The 500 GB version is 169 dollars and if you need more capacity you can find the 1 TB unit for 350 dollars. There are superior versions with 2 and 4 TB.
- Kingston SSDNow UV400. Series from another established manufacturer of solid state drives. You can find options with 240 GB for 88 dollars, 480 GB for 152 dollars and a 1 TB version (960GB) for 335 dollars.
- SanDisk SSD Plus. Another big manufacturer in the SSD sector, acquired by WD, with this series offering the 240 GB version for 77 dollars, the 480 GB for 139 dollars and the 1 TB for 260 dollars.
- OCZ TR150. Recovered after Toshiba purchased OCZ, it counts with memories from the Japanese manufacturer (one of the best in the sector) and offers units of 480 GB for 158 dollars and of 1 TB for 283 dollars.
- Crucial MX300. An example of a manufacturer using external memories, in this case by Micron, offering units in capacities of 275 GB for 99.99 dollars; 525 GB for 159.99 dollars and 1 TB for 289 dollars.
M.2 – PCIe SSD
- Samsung 960 EVO. It just landed this month on the market, but they will make a difference in the sector, offering an unknown performance for consumer storage: 3200 MB/s in reading speed. The 250 GB unit is sold for 130 dollars, the 500 GB costs 248 dollars and the 1 TB version 450 dollars.
- WD Black PCIe SSD. Another newcomer this year, a solid state drive from the leader of hard drives with 2050 MB/s in reading speed. The 256 GB costs 120 dollars and the 512 GB sells for 190 dollars.
- Toshiba OCZ RD400. Toshiba offers a MLC NAND model with its own 15-nanometer memories and amazing performance: up to 2600 MB/s in reading and 1600 MB/s in writing speeds. The 256 GB option costs 140 dollars and the 512 GB one 259 dollars.
- Kingston HyperX Predator. Another great choice among the M.2 format with speeds up to 1400 MB/s in reading and 1000 MB/s in writing. It offers an optional HHHL adapter to put it into a PCI slot if the PC does not have a dedicated M.2 connector. The 240 GB version costs 155 dollars and the 480 GB version 300 dollars.
- Intel SSD 750 Series. Device based on the PCIe board format with 400 GB of capacity (MLC, HHHL AIC, PCIe 3.0 X 4). It is especially focused on workstations and sells for 380 dollars.
- Samsung 960 PRO. Perhaps the most advanced SSD on the market and the fastest: 3500 MB/s in reading speed. The 512 GB unit sells for 324 dollars, while the 1 TB model costs 618 dollars.