The next software we used was the ATTO Disk Benchmark. The tool measures storage systems performance with various transfer sizes and test lengths for reads and writes. The benchmark performs file transfers ranging from 0.5 KB to 8192 KB. ATTO can be adjusted to do overlapped I/O, in a variety of queue depths. We tested the SSD using the benchmark's default settings, using 256KB file length performance and QD4. ATTO probably gives the most accurate results for compressible read and write data.

As you see above the drive's reading and writing performance with compressible files was pretty stable with files larger than 128KB. The average reading speed was about 540-550 MB/s and the writing speed was 500 MB/s.

However, the drive is suffering a bit in the sequential reading of 4KB or smaller files:

On the other hand, the Crucial M500 drive was very fast when it was writing such small, compressible files:

Going further to larger file transfers, the M550 drive remained fast, especially in the reading part: