Runs slower the longer it runs.

Defraggler program is very slow when it comes to large files. Still seems randomly slow to over 100 MB/s on small files. I've seen Windows Defrag use nearly 100% of HDD from time to time of "Active time" according to (Task Manager) even for very large files. Defraggler is at 50% of large, very large video files of an average of 100 KB/s read and 300 KB/s write speed. Drives are in RAID 0 and 128 KB Data stripe size and at SATA 3 at 600 MB/s of 2 TB. Who knows it could be the latest Windows 10 updates.

Windows 10 Pro v1803, Defraggler v2.22.995 (64-bit), Intel RAID.

DF has never the the fastest of it's breed.

it's why I never use it to defrag a drive, I just Analyse, sort the Fragments column in Descending order, select the top offenders and just defrag those.


then I repeat for the Size column.

and by top offenders I mean, those with > 20 frags or those > 20MBs (or whatever rocks your boat) :)