O&O SpeedCheck can simulate your Windows system in a fragmented and defragmented state. No data is written in the simulation, it simply reads test data from the hard disk. After completion of the simulation you will be shown a comparison of the two test times, and the possible increase in speed available to you. You can see just how much your PC could be accelerated by regular and thorough defragmentation.
The process is split into two phases: simulated reading of files that are fragmented, and simulated reading of the same files had they been defragmented. No real files are used for the reading. Files are read continuously one after the other on a hard disk level from the start of partition C:. During the reading process of fragmented files, the test files are opened and read operations are carried out according to the number of fragments the files are split into. This simulates how the operating system reads fragmented files. The reading process of the defragmented files is done in one read operation and loaded into the memory.