Expert's Rating
Our Verdict
The Samsung 850 PRO arrived just too late for last year’s round-up of the best SSDs, but even a year down the line it still has little serious competition in the stakes for the world’s best SATA SSD. It may be left for dust by more modern PCIe drives such as Samsung’s own XP941, but if you have a SATA-based PC and want to fit it with the best storage, take the closest look at the 850 PRO.
Price When Reviewed
$139.99 (250GB), $249.99 (500GB)
Best Prices Today: Samsung 850 Pro
The semiconductor division of the Korean giant has worked hard to make and market its solid-state drives, both to the computer industry where its drives are routinely installed in popular notebooks; and to the wider consumer audience that is now recognising the Samsung SSD as a drive of substance.
Samsung 850 PRO 1 TB review: what it is, why it matters
Samsung now has two series of SSDs available for computer upgraders, both designated 850 and then divided into 850 PRO and 850 EVO ranges. As may be evident from the naming scheme, the former PRO models are designed for highest performance, while the EVO range trades a little speed and endurance for a lower entry price.
What both series have in common though is the core silicon architecture that is now based on 3D NAND, or V-NAND, where the V is for vertical. This is the application of three-dimensional integrated circuit construction techniques, which just like human cities overcome the problem of over-crowding by building not sideways, but upwards.
Using 3D lithography, flash cells are built layer by layer on top of each other, 32 layers high here, giving a much higher density of storage that means that even for the 1 TB sample we tested, for example, the PCB inside only takes up two-thirds of the large 2.5-inch SATA case. See our group test: What’s the best SSD?
As with the 840 Series, the difference between PRO and EVO models is the type of flash cell employed; the 850 PRO uses more resilient multi-layer cell (MLC, and in particular the two-bit version) while the 850 EVO takes the latest three-layer cell (TLC), which allows more storage per square centimetre of silicon wafer, but loses out in long-term longevity and is slower to write to.
The 850 PRO is a great example of how Samsung can build an entire SSD with parts it makes itself to its own specification. So we have a Samsung-made MGX Controller chip based on a three-core ARM processor, 1 GB of Samsung low-power DDR2 RAM, and of course the NAND flash piled up to in Samsung’s new semiconductor process, still unique in flash memory.
The process size has actually gone up, from the 19 or 20 nm common to other brands, up to 40 nm, potentially conferring greater longevity while delivering better speed. This has inspired Samsung to offer one of the longest guarantees available, 10 years, matching the offer first made by SanDisk with its Extreme PRO SSD.
Samsung has also been working on the power efficiency issue, and with the help of a special sleep state that can be used by some laptops, publishes a lowest-in-class power consumption figure of just 2 mW when in this DEVSLP mode.
Samsung 850 PRO 1 TB review: cost, value
You can buy the Samsung 850 Pro 1 TB for £369 from Amazon
Samsung 850 PRO 1 TB review: benchmarks
Samsung 850 PRO 1 TB review: performance
The 850 PRO strolled through the simple sequential read/write tests, reaching 564 MB/s for reads and 534 MB/s writes in the ATTO benchmark test. Comparing the CrystalDiskMark results for standard random and compressible zeroes, we see the same level of performance at around 510 MB/s sequential reading and 480 MB/s writing.
The 4 kB single-thread random IO tests just place the Samsung ahead in the 4 kB random-read list with 36 MB/s, while the 89 MB/s write speed is still very impressive, a trend that continued when the SSD was stretched to its limits when fielding the high queue-depth test – the 403 MB/s random reads and 366 MB/s random writes makes the 850 PRO the top of the IOPS with 103,200 read IOPS and 93,700 write IOPS.
When running the comparable test from AS SSD it remained in the over-achievers class with 96,800 read IOPS and 81,400 write IOPS. The AS SSD benchmark awarded the Samsung 850 PRO an overall nominal score of 1145 points, the best overall result in this group. See our group test: What’s the best SSD?
Specs
Samsung 850 Pro: Specs
- Capacities: 256/512GB & 1TB
- Capacity tested: 1TB
- Price per GB: £0.36
- Tested 4KB performance: 36/89 MB/s
- Tested sequential performance: 508/482 MB/s
- Memory Cache: 1GB LPDDR2
- Controller: Samsung MCX
- Encryption: AES 256-bit, TCG Opal 2.0, IEEE-1667
- Flash technology: Samsung 40 nm V-NAND MLC
- Connection: SATA III 6GB/s
- Claimed power consumption: 5.8W active / 0.6W idle
- Warranty: 10 years
- Dimensions: 69.85x100x6.8mm