dfrgntfs.exe is a process associated with the Microsoft Windows Defragmentation application.
This process should not be terminated while running a defragmentation of the hard drive.
Non-system processes like dfrgntfs.exe originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that over time your registry suffers fragmentation and accumulates invalid entries which can affect your PC's performance. It is recommended that you check your registry to identify slowdown issues