O&O Defrag kan defragmentera disken enligt 5 olika algoritmer.
STEALTH. This method defragments all fragmented files and tries to consolidate them in order to optimize available free space. Here, speed and resource usage are the main considerations and the method is therefore not quite as thorough as the SPACE and COMPLETE methods. The STEALTH method has been designed with large fileservers in mind. It can, however, be used to great effect on workstations and other computers.
SPACE. All fragmented files will be defragmented, and then placed into the free slots in which they fit. This maximizes contiguous free space. This method is very quick and efficient and it does reorganize your volume, but not as thoroughly as the COMPLETE methods.
COMPLETE/Access. Files are sorted according to when they were last accessed. The files that have been accessed the least will be placed at the beginning of the partition, and those that are accessed that most frequently are put near the end. Seldom-used files are defragmented and will not need to be moved in future. Frequently-used files are placed at the end of the volumes. This strategy means that future defragmentation runs are as quick as possible, as fewer files need to be checked and defragmented.
COMPLETE/Modified. Files are sorted according to the date on which they were last changed. The files which have not been changed recently are placed at the beginning of the partition, and the files that have been changed recently are placed at the end. This option is a good one for file or database servers which contain files that have never been changed (e.g. system files), but where others are frequently modified. (e.g. database files)
COMPLETE/Name. Files are sorted alphabetically from the beginning to the end of the partition. This leads to quick access to files in a directory. When Windows starts up, many system files will be read in sequence from the \WINDOWS and the \WINDOWS\system32 directories (DLLs, system drives, etc.) and the start-up time will therefore be shorter.