Defraggler vs Window's built in shows drastically different numbers

[Elixer]

Using Window's "optimize Drives", it shows 0% fragmentation.
Using the latest version of Defraggler shows 42% fragmentation.

That is a huge disparity.


I am curious if anyone else has ever notice/seen this before ?

 

[uberman]

I used Defragler for a month or two and I liked the optomization but really didn't notice any great changes. Your right though. I believe different defraggers sometimes use different processes. I'm a compulsive defragger which meant I bought the next version of Diskeeper. Diskeeper works great, but it will set you back $50 or so.

 

[Mike64]

I've never run the Windows defragmenter and Defraggler literally side-by-side, so I don't know if my experience will be useful, but for what it's worth...

Until recently, I had Windows defragmenter set up to run weekly defrags on my 1TB data disk automatically. I didn't pay much attention to it, in fact, I'd forgotten that I'd even set it up. But I would run Defraggler manually every couple of months (when I thought of it, basically), and invariably got readings above 10%. I'd run Defraggler manually, and knock it down to <= 5%.

Then a couple of weeks ago, I finally switched and started using Defraggler to do scheduled runs instead of Windows. When I checked the state of the HDD manually with Defraggler a couple of days ago, fragmentation was down to 5%. So superficially at least, it appears that Defraggler is doing a better job.

 

[schmuckley]

Ultradefrag is better.

 

[coffeejunkee]

A possible explanation might be that Windows doesn't look at free space while Defraggler does. At least it appears that way of you look at the graph during defragging. So Windows just keeps files together, while Defraggler also moves them to the beginning of the disk.

I must say that I don't really notice too much improvement from defragging anymore. Big platter disks are fast enough nowadays and with the os on an ssd there's no constant writing and deleting anymore. I'm also worried about the increased strain caused by overly enthusiastic defragging.

 

[code65536]

It depends on how you define fragmented.

1) If you have a 4GB file split into two 2GB fragments, would you consider that file to be fragmented and in need of a defrag? I wouldn't. Once a file fragment is beyond a certain size, it doesn't really matter since, for all practical intents and purposes, it's not fragmented.

2) If you have a 4GB file split into two 2GB fragments and a 4MB file that's unfragmented, what is the percentage of fragmentation? Is it 99.9% since it's 4GB fragmented and 4MB unfragmented? Or is it 50% since it's 1 file fragmented and 1 file not?

3) Edit: and the free space comment above, too

 

[krose]

I've been using sysinternals contig utility. Works for me.

 

[blankslate]

One reason is that MS engineers arrived at the conclusion that the speed and size of modern drives is such that there may not be as much benefit to defragmenting large files such as videos or data files for games as there is with defragmenting smaller files.

As such the Windows defragmenter may look at a large defragmented video file and decide that leaving it defragmented won't impact the user as much because the OS and media program will have time to access the file on the HD and the user won't notice any performance degradation when watching it.

While many 3rd party defraggers will report any deframentation to the user regardless of the size of the file.

That might explain some of the disparity

http://blogs.msdn.com/b/e7/archive/...d-engineering-the-windows-7-improvements.aspx

In Windows XP, any file that is split into more than one piece is considered fragmented. Not so in Windows Vista if the fragments are large enough &#8211; the defragmentation algorithm was changed (from Windows XP) to ignore pieces of a file that are larger than 64MB. As a result, defrag in XP and defrag in Vista will report different amounts of fragmentation on a volume.

So, which one is correct? Well, before the question can be answered we must understand why defrag in Vista was changed. In Vista, we analyzed the impact of defragmentation and determined that the most significant performance gains from defrag are when pieces of files are combined into sufficiently large chunks such that the impact of disk-seek latency is not significant relative to the latency associated with sequentially reading the file.

This means that there is a point after which combining fragmented pieces of files has no discernible benefit. In fact, there are actually negative consequences of doing so.

For example, for defrag to combine fragments that are 64MB or larger requires significant amounts of disk I/O, which is against the principle of minimizing I/O that we discussed earlier (since it decreases total available disk bandwidth for user initiated I/O), and puts more pressure on the system to find large, contiguous blocks of free space.

Here is a scenario where a certainly amount of fragmentation of data is just fine &#8211; doing nothing to decrease this fragmentation turns out to be the right answer!

This is one reason why I like Auslogics Disk Defrag. You can set that program to ignore fragmented files larger than a certain size. I choose to have it defragment files smaller than 100MB.

Every once in a while when I set Auslogics to move more frequently accessed data to the faster areas of the drive I will set it to ignore no files.


I have also used Ultradefrag. I like it and have it installed but for most of my defragmenting needs Auslogics takes care of it with an interface that I find a bit more streamlined.



....

 

[corkyg]

Don't forget - there is a difference between defragging and optimization.