CrystalDiskMark is a synthetic benchmark that tests both sequential and random small and mid-sized file transfers using incompressible data. It provides a quick look at best and worst case scenarios with regard to SSD performance, best case being larger sequential transfers and worse case being small, random transfers.
CrystalDiskMark Benchmarks
Synthetic File Transfer Tests
Overall, the Samsung 840 did very well in our CrystalDiskMark tests. Again we see, in the sequential and 512K transfer tests, that this drive posts strong read scores and less impressive write scores; in both, it scored at the top in the former and at the bottom in the latter. In the 4K QD32 test, however, that write score came up significantly.
While the 840's read score in the 4K transfer test was solid, it was actually the write score that topped the charts for a change.