Samsung SSD 850 Pro 256GB, 512GB and 1TB Comparisons and Tests

In a few significant ways, the 850 Pro is the most advanced 2.5in SSD on the market. So far, Samsung remains the only company to sell products based on 3D NAND, where layers of cells are stacked on top of each other, as well as horizontally. Samsung’s own implementation of this idea is called 3D V-NAND.

Improved chip density due to shrinking transistor and cell sizes alone has hit a brick wall. As cells get smaller, their reliable storage of data becomes increasingly difficult. Smaller cells mean less space between them, meaning a greater chance of interference when a neighbouring cell is passed voltage for a write or erase command.

Smaller floating gates also means greater insulator wear, reducing drive endurance. Instead of increasingdensity via traditional means, when cells are layered on top of one another with V-NAND, larger cells can be used, which is why Samsung can use 40nm MLC flash in the SSD 850 Pro, mitigating the aforementioned issues.

V-NAND has real-world benefits too, from improved performance to impressive endurance figures. All 850 Pro drives are rated for 150TB of writes, considerably more than rivals. Samsung is backing this up with a ten-year warranty too. It helps that Samsung is also the only SSD manufacturer to control every aspect of its products, including the NAND flash chips, the controller design, the firmware and the DRAM cache. The triplecore MEX controller in the 850 Pro runs at 400MHz, with 256MB of LPDDR2 cache in the 128GB model, 512MB in the 256GB and 512GB models, and 1GB of cache in the 1TB 850 Pro.

In the CrystalDiskMark sequential read test, all three 850 Pro drives claim the top spot with the same speed of 551.4MB/sec, while in the write tests, it jostles for first place Samsung’s 850 Evo drives. Although it doesn’t come top in every random read and write test, the 850 Pro again comes close, and once again claims a close second place to the 850 Evo in 32 and 64-queue-depth tests. Meanwhile, in Iometer all three 850 Pro drives managed the best IOPS result by some margin, being 1,400 points ahead of the nearest rival.

There are two snags that prevent the 850 Pro from achieving total domination. Firstly, the sheer scale of the engineering effort that went into the 850 Pro is reflected in the prices: 52p per gigabyte for the 256GB model, 50p for the 512GB and a more reasonable 42p for the 1TB. You’re paying considerably more than with the majority of other brands.

Also, the outstanding synthetic performance results don’t translate into similarly impressive real-world performance gains. Although it doesn’t come top, the 850 Pro does well in the PCMark 8 Photoshop Heavy and Microsoft Word traces, but any advantage is measured in a fraction of a second, too small to make any noticeable difference in use. Any difference in boot times is similarly tiny, with the 1TB 850 Pro being 1.8 seconds slower than the 512GB model.

Conclusion

The 850 Pro’s advantage in synthetic tests doesn’t result in significantly better real-world performance, and most people would struggle to notice the speed difference between the 850 Pro and a more affordable SSD. However, the 850 Pro’s superb IOPS performance, ten-year warranty and solid endurance figures make it a brilliantly fast choice for workstation users.

VERDICT

The 850 Pro’s outstanding performance and endurance is wasted on a consumer desktop PC, but it’s ideal for workstation users.

OVERALL SCORE

SAMSUNG SSD 850 PRO 256GB – 78

SAMSUNG SSD 850 PRO 512GB – 81

SAMSUNG SSD 850 PRO 1TB – 85