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. AS SSD includes a sub suite of benchmarks with various file pattern algorithms but this is difficult in trying to judge accurate performance figures.
The MX500 tops the charts of the 500GB class 2.5in SSD's we've tested when it comes to the AS SSD benchmark in terms of read performance. Although the write performance, with a score of 506 is very good, Crucial's BX300 drive actually gave a slighty better write score of 515.