I'd suggest you search online for stuff like "$LogFile causing high disk usage" or "$Mft cause high disk usage" and see what other people are talking about/suggesting. Doing a quick search, myself, I found What Is NTFS Volume Log ($Logfile) And Why Is It Causing Disk Activity In Windows 7 which seems to provide some suggestions (note: I have not tried these suggestions myself, and would advise caution if you use them; always test in something other than production if possible )