I used Auslogics Disk Defrag the other day and it slowed my machine down. This defragger takes a while but does a very good job and after you run it next time it doesn't take as long. My machine was still slow after I ran the defragger but not as slow as when it ran the other defragger and I ran the free space defragger and it's even faster now!
I really like this software. I am impressed!