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 DC500M was a wee bit faster than the DC500R for both reads and writes in the ASSSD benchmark with a read score of 476 and writes at 529.