How is the performance score determined?

The score is determined by the AS SSD Benchmark program. The tool includes six synthetic tests as well as three copy tests. The synthetic tests determine the sequential and random read and write performance of the SSD. These tests are performed without using the operating system cache. In the Seq test, the program measures how long it takes to read or write a 1 GB file. In the 4K test, read and write performance is determined using randomly selected 4K blocks. The 4K-64-Thrd test corresponds to the 4K procedure, except that read and write operations are distributed across 64 threads. This test should show differences between IDE mode, where Native Command Queuing (NCQ) is not supported, and AHCI mode on SSDs with NCQ. The additional compression test can measure SSD performance depending on data compressibility. This is especially important for controllers that use compression to increase performance and extend cell lifespan. In the first three synthetic tests and the compression test, the test file size is 1 GB. Finally, the SSD access time is determined, where read access is measured across the entire SSD capacity (fullstroke). The write access test, on the other hand, is performed with a 1 GB test file. At the end of the tests, three values are output for read, write and overall performance. The results of the compression test are displayed as a graph. The X-axis indicates data compressibility, from 0% (not compressible at all) to 100% (fully compressible). The Y-axis indicates the achieved data rate. In addition, the measured values in MByte/s can also be displayed as I/O per second (IOPS).

The formulas for the scores are:

Read result = Sequential read rate * 0.1 + 4K read rate + 4K-64thrd read rate
Write result = Sequential write rate * 0.1 + 4K write rate + 4K-64thrd write rate
Total result (SCORE) = Sequential write rate * 0.15 + Sequential read rate * 0.1 + 4K read rate * 2 + 4K write rate + 4K-64thrd write rate + 4K-64thrd read rate * 1.5

Copy tests: In the copy tests, the following test folders are created: ISO (two large files), Programs (typical program folder with many small files) and Games (a game folder with small and large files). These three folders are copied using the operating system’s simple copy command. The cache remains enabled for this test. The real-world tests show SSD performance during simultaneous read and write operations. Results may vary depending on the Windows operating system used. Compression test: Read and write speed is measured depending on data compressibility. For this purpose, zeros are deliberately inserted into random data. The zero areas compress well, the random data is practically not compressible at all.