On paper, a Samsung 850 Pro higher data throughput (in MB / s) and a larger number of IOPS '. So why spend more money on a "slower" 845DC Pro?
Well, that puts the speed very quickly when z. B. server systems in small quantities and writes the application (eg. B. Database) after each write operation makes a write cache flush to ensure that the data actually land on the medium.
Example: One of my databases has the write cache of the HDD disabled and writes in 4KB units on the disk. The 850 Pro creates there's about 3.1 MB / s (794 IOPS). The 845DC Pro creates in exactly the same test 28,8MB / s (7373 IOPS), which is more than 9x faster. For most people, the application should not be given and the plates behave almost the same rate. Nevertheless, there are also "ordinary consumers" a few advantages, such. As end-to-end protection, making corrupt data extremely unlikely or capacitor backed cache, which ensures that data but at least 512MB large cache during a power outage not end up in Nirvana, but still can be written to the SSD.
Comparable SSDs from other manufacturers are either slower and more expensive, or (if the same speed or faster) much more expensive, at least what I could discover so (z. B. S3700 Intel, Seagate, HGST).