CrystalDiskMark is an open source disk drive benchmark tool for Microsoft Windows from Crystal Dew World. Based on Microsoft's MIT-licensed Diskspd tool,[2] this graphical benchmark is commonly used for testing the performance of solid-state storage.[3][4] It works by reading and writing through the filesystem in a volume-dependent way. It generates read/write speeds in sequential and random positions with varying numbers of queues and threads.[5] Solid-state drives tend to excel at random IO, as unlike hard drives, they do not need to seek for the specific position to read from or write to.[6]