Piriform's Defraggler says one thing, Windows Defrag says another?

[SlackerITGuy]

So here's the dealeo, I just finished doing some HDD cleaning, and as a result I wanted to defrag my drive with Defraggler, everything went smooth as silk, but I saw that Defraggler was telling me (after the defrag) that my drive was still 17% fragmented.

After running it 1 more time, it was telling me the same thing, so, after seeing that, I went and booted up Windows Defragger, and did a quick analysis on the drive, it said the drive was 0% fragmented.

Which one should I believe?

 

[LiquidSnak]

I would be tempted to believe windows at this point, especially after defragging twice.

 

[SlackerITGuy]

I would be tempted to believe windows at this point, especially after defragging twice.

That's what I'm thinking.

The weird thing is, I haven't downloaded/copied/etc, anything that would be worth the 17% fragmented number, just uninstalled a couple of games/apps.

 

[LiquidSnak]

Maybe uninstall with revo, then reinstall defraggler and see what it says?

 

[Barman58]

This could simply be a difference in the way the applications determine fragmentation. Certain files cannot be de fragmented for various reasons, (Pagefile is one I think) .

it may be that Windows is actually saying is that of the defragmentable files 0% are fragmented, whilst defraggler is stating that there is fragmentation of 17% of all files

 

[SlackerITGuy]

Sounds reasonable.

Oh well, I was thinking about creating a support ticket over @ Piriform's site, but since I'll be doing a clean Windows install in the short term, not sure if it's worth the effort.

(I still think is pretty weird since I did absolutely nothing to warrant a 17% fragmentation number, the most I've seen with my drive is 1% lololol).

Thanks anyways fellas. Have a good one.

EDIT: and just like that, I created a thread over at Piriform's Forums lolol.

 

[DBone]

I know this is a thread resurrection, but I wanted to comment on it. Defraggler shows drives still being fragmented because of restore points. If you are using Defraggler, you can delete all restore points, defrag and then add a manual restore point. After defragging, you'll notice that Defraggler shows 0% fragmentation.

 

[Corazon]

Defraggler will also clue you in on your pagefile fragmentation. If pagefile.sys isn't in one nice big green chunk, time to either defrag your system offline (from a boot disc) or disable pagefile, reboot, delete C:\pagefile.sys (as it's sometimes left over), defragment the drive and then recreate the pagefile.

 

[kado897]

I think that Windows Defrag reports % of files and Defraggler reports % of bytes in fragmented files. One or two large fragmented files can cause this discrepancy.

 

[cluberti]

It's also worth noting that the inbox defrag ignores any files that are larger than 64MB when generating fragmentation statistics, whereas most other defragmenters do not. The Engineering Windows 7 Blog had a post specifically about disk fragmentation in Windows 7, and why defrag might behave differently than people expect:
Disk Defragmentation

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 – 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 – doing nothing to decrease this fragmentation turns out to be the right answer!

As I've said many times, using a 3rd party disk defragmenter might be necessary to quickly clean up a drive that's been left alone for long periods of time, but for ongoing maintenance the inbox defragmenter is very good, and very smart.

 

[rreed87139]

I tried a couple defragmenters. Defraggler and others reported different numbers. Actually I could do advaced defrags and they would always tell me that I could defrag and get better performance after the thorough defrag. And it seemed like my disk always had activity. I believe I read somewhere that the Diskkeeper model is what windows uses. I can run a full defrag, let it complete, and run it again with the second run completing in under a minute. Indicates to me that the scan engine is consistant.