I've been trying out mst defrag, o&o and diskeeper on my drone PC (win xp), which is used for filesharing and downloading. I download approx 2 gig a week of 50 files of varing sizes, machine is left unattended most of the time, running 24/7. If I dont defrag, after a week file copy/move operations do take noticaly longer and also when I reshare files hashing takes longer with a large proportion of the files are fragmented. I really love the idea mst defrag, but my only issue is that it keeps trying to defrag movie clips im downloading, which are quite big so the file takes some time to defrag, then more of the file is downloaded which then causes the file to get fragmented, which mst detects and trys to defrag and we get stuck in a silly loop. Diskeeper, we use this at work and I tried it at home and worked nicely on set it and forget, I know it does'nt do a perfect defrag (part of the multi pass design), but it does a decent job at keeping drive perfomance good enough, ran a few times a day, but nice and quick defrag passes. O&O, used the auto defrag option, its did nothing but stealth defrags (seemed to run once a day). Defrags files and will move these files only to help consolidate space... problem is that this stealth method left files scattered across the hdd, which in turn would cause big files to get more fragmented than with diskeeper or mst as lack of contious space to put some of my bigger files, which in turn would mean stealth defrag times never settle down to an unobtrusive time like with diskeeper. I don't understand why a space defrag was never executed occasionaly to help prevent this issue ? So at the moment it looks like diskeeper is the best option to use due to its lack of flaws, which these other 2 defraggers have. Maybe if o&o had a longer trial it would eventually run a space defrag, or does it just do nothing but stealth defrags using the one button defrag ? I personally like the concept of how MST defrag works the best, has anyone else tried it on a highly active partition with large files ?