I have tried DIRMS and can say that for me the program is far better than the the defrag that comes with WindowsXP. After running the XP defrag and rebooted my system, I went into windows explorer and opened some files. I then ran the DIRMS program and moved a lot of files around. I could feel a differance in boot speed along with how fast files opened in windows explorer. I am now trying out O&O defrag which has the nice GUI that DIRMS is missing but I have not noticed any increase in speed over the DIRMS defrag, nothing like I seen going from the WindowsXP defrag to DIRMS. DIRMS is free and O&O defrag is not. How much is a GUI worth? DIRMS does not have all the features but then again it does not have all the baggage that the other programs have either. IMHO DIRMS is alot better than the WindowsXP defrag.