The 850 Pro’s large file performance is blisteringly fast, but its small file performance is relatively disappointing
Capacity: 256GB, Interface: SATA3, Claimed read: 550MB/s, Claimed write: 520MB/s
The Samsung 850 Pro is the first Samsung SSD to use a new type of NAND flash: 3D V-NAND. Although it’s a very complicated technology, 3D V-NAND is potentially very important for the future of SSDs.
3D V-NAND allows Samsung to stack the cells in NAND flash chips vertically as well as horizontally, thereby increasing the capacity of NAND flash chips in a SSD without having to rely on ever smaller manufacturing processes that are increasingly difficult to achieve. According to Samsung, 3D V-NAND is made using a 40nm process compared to the 20nm process of most other competing SSDs.
The increased storage capacities made possible by 3D V-NAND remains theoretical for now as the 850 Pro range tops out at 1TB just like previous Samsung SSD ranges. Samsung does claim that 3D V-NAND has performance benefits, though. We were initially sceptical as the 256GB 850 Pro, while fast at copying small files, was not significantly faster than the small file writing speed of other SSDs, with the 850 Pro writing small files at 102.1MB/s and reading them at 77.6MB/s.
It was a completely different story with large files, where it blazed ahead, writing large files at a blistering 746.1MB/s and reading them at 480.2MB/s. We ran the test several times to confirm these figures as, in the past, such high results were confined to SSD RAID arrays, but the 850 Pro is easily the fastest SSD we’ve seen in this test. We’re certain that these speed improvements are due to 3D V-NAND, as the 850 Pro has the same 512MB DRAM cache and tri-core MEX controller as the 840 EVO, albeit with newer firmware.
We suspect that the 850 Pro’s performance would be even faster if it were available with PCI Express-based interfaces such as M.2 or SATA Express. For now, the 850 Pro sticks with the much more widespread SATA3 interface with a 2½in form factor. The 850 Pro is rated for a maximum daily transfer load of 80GB and is backed by a five-year warranty, which is second in length only to the 10-year warranty of the Sandisk Extreme Pro.
The Samsung 850 Pro is a cracking SSD, but you pay a high price for its incredible performance. The 256GB model costs £140 or 55p per gigabyte. The 512GB Crucial MX100 costs just £150 or 29p per gigabyte for twice as much storage. Although the MX100 isn’t as fast at copying large files, it’s still faster than many other SSDs, and it does outstrip the 850 Pro’s performance when copying small files. Overall, the MX100 is still our favourite SSD and is better value the Samsung 850 Pro.
|Controller||Samsung triple-core MEX|
|NAND flash type||40nm 3D V-NAND|
|Warranty||10 years RTB|