MK_Matt

Thanks for the replies guys. It is a desktop PC and my main drive is an SSD, so performance of my storage drive doesn't need to be to of the line. Also, as @mta noted, the performance of WD Green drives is actually pretty good. Anyway, this is all besides the point. As I stated in my original post - the defrag speed was much quicker using a different defrag program, it ended up doing more in 1 hour than Defraggler did in 8 hours. This points to an issue with Defraggler and not my hard drive. It seems as though for whatever reason, Defaggler would only use 30% of my hard drive's transfer capacity, while the other defrag solution used 100%. Could it be a compatibility problem with something else I have installed or with Windows 8.1?

I'm also experiencing this (with the free version). I left it defragging a 30/40% fragmented 2TB volume overnight (8+ hours) and it was only at 40% complete in the morning. It also said there was >1 day left. I looked at the disk utilisation (active time) in task manager and it was at about 30%. I cancelled the operation and tried using another free defrag solution, it is using 100% disk active time and has reached 10% in only minutes. I'm running Windows 8.1 (clean install just last week) and the drive is a 2TB WD Caviar Green. Any ideas what could be causing this? Thanks.