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.
The SanDisk Extreme II SSDs we tested performed very well in the various CrystalDiskMark tests. The SanDisk drives led the pack in the sequential transfer test, but finished at the bottom in the 512K transfer test. With 4K transfers at the lower queue depth, the SanDisk drives fell somewhere in the middle of the pack, but they came roaring back in the 4K QD32 transfer test and offered some of the best performance once again.