The ATTO Disk Benchmark 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. The test was run with the default runs of 0.5KB through 8MB transfer sizes with the total length being 256MB and QD4. ATTO probably gives the most accurate results for compressible read and write data:

The latest build of ATTO Disk Benchmark shows that the Toshiba XG6 is hitting up to 3 GB/s read and 2.83 GB/s write at a queue depth of 4:

The Tosghiba XG6 1TB SSD takes the overall win in both the read and write tests: