We proceed with the AS SSD benchmark, which contains five synthetic as well as three practical tests. The synthetic tests determine the sequential and the random read / write performance of an SSD. These tests are carried out without using the operating system's cache. The Seq-test measures how long it takes to read and write an 1GB file. Most importantly, this sequential benchmark uses incompressible data for all of its transfers.

The 4K benchmark tests the read and write performance for random 4K blocks. The 4K-64-THRD-test corresponds to the 4K procedure except that here the read and write operations are distributed on 64 threads.

Both the sequential reading sequential writing performances are very high. The drive produced 408.53 MB/s read speed, and 283.10 MB/s write performance. It is obvious that this performance is higher than what you would get from SandForce-based SSDs, which are not fast with incompressible data.

Single-threaded 4K IOPS performance delivers a great 21.50MB/s read and 74.39 MB/s write, while the 64-thread 4K reads recorded 156.380MB/s and write performance was 224.17 MB/s.

In addition, although the drive showed great access times for read (0.051 ms,) it was slower during write (0.274 ms).

In the following test, the Crucial m4 256GB SSD is reading and writing files, which have been partially of fully compressed. The drive reported a consistent performance: