They do NOT all run at the same speed.

It largely depends on how the app handles defragging...for example, TechTool Pro does it by moving files around to reassemble the fragments...now maybe this has changed in 3.x, but that meant ERRORS and incomplete optimizations; try having a large file it has to move..say 300 megs...and having like 250 megs free...it won't do it!

Norton Speed Disk will, because it moves the smaller fragments around, not the big files...but it too will give errors if you're REALLY tight on space and have large files. Norton's faster, in my experience.

PlusOptimizer? Some people like it..I love the "Anchor" feature, you can set a file to NOT be moved at all during a defrag...but it's slower than molasses, at least on my machine. I bought it when it came out, and talked to Alsoft about it. They just kept trying to attribute the slowness to LARGE files on my drive, which I removed, did it again and it was still pathetically slow. They really never gave me a good answer for it..and it's STILL slow, I tried it again the other day..thought the new one was faster...NOPE!

Feel free to disagree, anyone... They ALL do what they are supposed to and do it well, just in slightly different ways. I can't say how much of speed in defragging is contributable to processor speed, I don't know. But maybe G3's and G4's handle it better than my slowass 150mHz SuperMac does.

My choice is Norton, it works well for me. Just a reminder: Don't have all the directory check and repair crap on in prefs of Speed Disk. ALWAYS use DiskWarrior first before defragging and leave it all off in Speed Disk. Alsoft DiskWarrior is the finest directory-rebuilder money can buy. If you don't have it, get it! :-)