I have been reading about Diskeeper 15. Their website makes a lot of big claims. But, do you really notice any real world difference over Windows 7/8/8.1 built-in Disk Defragmenter?
Disk fragmentation is the bane of every 1950's-tech-based storage device. Namely spinning HDD. HDD was never intended to be used the way we used them today. Substitutions for main memory. SSD is simply so much better. But this thread isn't about HDD vs. SSD. The only defraggers that deliver any marked performance gains are ones that can do file placement optimization. Defraggers that can consolidate and place in order the most active data. Program files, temp files, data files. This is what minimizes the impact of the slowest part of the computer. The head actuator, and its movements as it seeks from track to track, file to file. Things like movies, photos, music.. That is usually 1-off access and can be highly fragmented with no loss in performance. The system buffers absorb any latencies nicely.
Diskeeper also claims that fragmentation affects SSDs. Have a look at the video titled "Why Fragmentation is Still a Problem with SSDs" here.
They are worried about their business. Most subjective (spinning) HD defragmentation effects are placebo in nature.
I think publishers of defrag software have a long history of exaggerating the benefits of running their software. One thing that I've always failed to understand, is how a badly fragmented hard drive can cause crashes as is sometimes claimed. For example:
Just about everything is better than the utilites bundled by Microsloth , IMO. A good example is the "Everything" search tool ..... it beats the Windows search tool in so many ways. I've used Defraggler for years , tried Auslogics but went back to the Piriform tool. If I had one gripe about Defraggler , it would be that you sometimes have less free space after running it. It tends to make the most recent restore point unnecessarily large. But that is an easy fix ...... create a new restore point after the defrag , then delete the previous one
Going from a heavily fragmented disk to a windows-defragged disk, you see marginal gains. But going to a file placement optimized disk you see measurable and real-world gains.
It's possible buffers could overflow while waiting on disk i/o. But then that indicates you have an os problem.
I have questioned that myself. By the way. I messed about with Auslogics Disk Defrag the other day. It seems a nice program.