Three Samsung 850 EVO SSDs tested – What is the fastest EVO drive?
Samsung released its 850 EVO series of solid state drives six months ago, but at the time limited the range to 2.5″ SSDs. The South Korean company has now also released its mSATA and M.2 variants of the drives. released, both with sata interface. We took care of the small SSDs to find out the differences with the 2.5″ version.
Which drive should you choose if you have the choice for your desktop with M.2 slot? Do you keep your 2.5″ mass storage drive in your laptop and build in an mSATA or M.2 SSD for your operating system? Does it really matter what type of drive you choose, or is it just the price and does capacity matter?In addition to the three variants of the 850 EVO drive, we also include one of the most popular drives, the MX100 in 256GB capacity, in the comparison.
Samsung was the first manufacturer to make so-called 3D memory available for consumer drives. Samsung calls this memory 3d-v-nand. There are no less than 32 layers of memory cells stacked on top of each other within a piece of silicon. Samsung therefore needs a smaller surface to achieve a memory density. As a result, a larger lithography process can be used, which would make the production of the chips cheaper. Moreover, it allows the company to switch to larger cells: from 19nm to 34nm. This reduces the chance of reading and writing errors. The MGX controller is used in all versions except the 1TB drives to control this type of memory: a slightly older MEX controller is used in the 1TB drives.
Performance: AS SSD
We start with a synthetic benchmark: AS-SSD. We test the sequential transfer speeds you see when copying a large file. The random read and write performance, the 4K performance with 64 threads, is also reflected in this graph. That performance gives an impression of the speed that your operating system achieves on the drives, where many small files are read and written
We don’t see any major differences in sequential reading, but the Crucial is slightly slower in writing. With the small 4K files, we see little difference when reading, but when writing, the smaller drives turn out to be a lot slower than the larger capacities. That’s because the controllers can write to fewer chips at a time.
Achievements: traces
With traces we play back recorded disk activity: we record and reproduce all disk activity, for example when installing programs or playing games. This allows us to measure the performance of the drives during installation, startup and normal use.
For the traces that include Windows startup, we see little difference between the size of the drives, only the 1TB version is a bit faster than the rest. We also see no major differences between the capacities or the interface in the Home & Office trace, which reflects normal use. The 1TB drive is a bit faster for games, while the MX100 from Crucial lags behind a bit. In the weighted average of all traces, contained in the Storage index, we see that the 1TB drive is somewhat faster than the rest. Again, this will be due to the greater parallelism with which the memory can be accessed.
Degradation
We ran the traces four times: the first time with only the trace data on the SSDs, the second time with half of the remaining free space written to it, and the third run with the drive almost full. For the fourth run, only the space needed for the traces is free.
run of the 850 EVO drives is always slower than the other runs. So there is hardly any degradation in the following runs, but if the drives are completely full, the 500GB capacities do have a drop in performance.
Conclusion
Unsurprisingly, all drives perform quite similarly at equal capacity. Whether it’s a 2.5″ drive, an mSATA drive or M.2 SSD, all variants simply have a SATA 600 interface. However, you can see that the larger drives generally perform better: from You get the most out of your SSD with 250GB. Other than due to a very limited budget, the 120GB version will not be very popular at all: the ‘sweet spot’ for SSD capacities has now firmly shifted to the 250GB capacities. variants are more attractive in terms of price, but you don’t have to choose them for the time being for performance. However, the price per gigabyte of the larger drives is slightly more attractive. That also applies to the 2.5″ drives: they are slightly cheaper than the more compact variants.