UltraDefrag is a powerful Open Source Defragmentation tool for the Windows Platform. It makes use of the same defragmenting API used by many other windows defrag utilities, both open and closed source. However, UltraDefrag has many features that makes it unique. It can defragment any system files including registry hives and paging file. Also one of the main goals of UltraDefrag is doing the job as fast and reliable as possible.