AS SSD is a great free tool designed just for benching Solid State Drives. It performs an array of sequential read-and-write tests, as well as random read and write tests with sequential access times over a portion of the drive. It uses incompressible data samples which many drives struggle with, so results can be viewed as the worst-case scenarios.
AS SSD includes a sub suite of benchmarks with various file pattern algorithms but this is difficult in trying to judge accurate performance figures.
In the AS-SSD benchmark test, the 990 EVO Plus read score of 2986 is 108 points better than Samsung's 990 PRO but the PRO has a slighter better write result.