The Samsung 860 series of solid-state drives (SSDs) has some big shoes to fill.
These new drives, the 860 Evo and the 860 Pro, are intended to succeed the popular 850 series which, according to Samsung, is the best-selling line of SSDs in major markets such as the United States and Europe.
Launched in 2014, the 850 series was so successful because it uses Samsung's V-Nand technology, in which memory chips are stacked vertically to increase storage density.
This technology, also known as 3-D Nand, has lowered the cost of SSDs and helped to increase their maximum storage capacities from hundreds of gigabytes to terabytes in recent years.
While the 850 series started out using a 32-layer V-Nand design, it was upgraded to a 48-layer design in later variants. The new 860 series pushes this further with a 64-layer design. It also gets an updated controller, which manages the SSD's flash memory to improve performance, correct errors and maximise the lifespan of the SSD.
The difference between the 860 Evo and the 860 Pro lies in the type of flash memory cell used. The Pro variant uses 2-bit MLC (multi-level cell), while the Evo uses 3-bit MLC.
Thus, the Evo holds more data (3 bits versus 2 bits) in each cell, which translates to it being cheaper, but also leads to lower write endurance compared with the Pro. Write endurance measures how much data can be written to the SSD during its lifespan - the Pro has twice the write endurance of the Evo.
PRICE: From $149 for 860 Evo (250GB); from $199 for 860 Pro (256GB)
INTERFACE: SATA 6Gbps
WARRANTY: Five years
VALUE FOR MONEY: 4/5
Samsung has reduced the Pro's warranty period from 10 years for the 850 Pro to five years for the 860 Pro. Meanwhile, the Evo retains its five-year warranty.
In terms of performance, the 860 series is slightly faster than the 850 on paper. The sequential read and write speed for the 860 Pro is rated at 560MB/s and 530MB/s respectively, compared with 550MB/s and 520MB/s for the 850 Pro.
The 860 Evo has the same sequential write speed as its predecessor (520MB/s), while its sequential read speed of 550MB/s is only 10MB/s faster than the 850 version.
In short, the 860 series does not offer a significant leap in performance from its predecessor. This is not a surprise, as the SATA 6Gbps interface used by this mainstream SSD series is the bottleneck here.
On the other hand, the write endurance of the 860 series has been doubled from the 850 series, which is a big improvement.
To test the 860 series, Samsung sent The Straits Times the Pro and the Evo review units in the 2.5-inch form factor. The Pro is available only in this form factor, while the Evo comes in the mSATA and M.2 form factors.
In my testing, the 860 Pro and the 860 Evo managed around the 563MB/s mark for sequential read speed using the CrystalDiskMark 6 storage test. The sequential write speed was similar for both models at about 533MB/s.
The overall storage score in PCMark 8 was also near-identical for the two.
The 860 Pro scored 5,009, while the 860 Evo managed 5,001. In other words, users are unlikely to notice the difference between the two in everyday usage.
Other SSD makers have stepped up their game in recent years. For instance, Crucial just started selling its MX500 SSD using a 64-layer 3-D Nand flash. The MX500 is slightly cheaper (from $135 for 250GB) than the 860 Evo, though its write endurance is not as good as the Evo.
• Verdict: Samsung's latest mainstream SSDs offer slightly better performance and much better write endurance compared with its previous 850 series.