Boot performance monitoring, what you need to know
New data subsequently saved to the same disk fills in the gaps and keeps existing data separated into chunks on various parts of that disk. Fragmented files slow computer function in general, and the boot process in particular, because a computer's read and write head has to search for all the data pieces before it can open any files. The data in defragmented files is located in one place, and therefore, easier to open. Boot optimization through defragmentation joins the scattered data together by using that data to close the gaps left by deleted files and programs that are nearest its companion data. These separate portions of data are then combined and rewritten into one complete data file, and so on until the whole disk has been defragmented.