How much free space needed for a defrag

[Rudyard]

I once had problems defragging my HDD in that the windows defragmenter kept saying I needed to defrag even after a defrag (and the fragment dialogue bar was the same before and after) and someone once told me I needed something like 30% free for a decent defrag.

Im just wondering how much is needed free cause I cant remember and am in serious need but have very little space left.

I have a 120GB HDD and have only 3GB free....what do i need to get to to make it have an effective defrag?

[dialysis1a]

I believe you need at least 15% (8GB)

[Xylob the Destroyer]

depends on the defrag program, but you'd pretty much always need at least as much free space as the largest fragmented file takes up.

[Krispy Kritter]

If that drive is also your C: drive, then some of that space is also being set aside for your swapfile. You likely need to do a little cleanup or simply replace the HDD with a larger one. 500GB drives are going for less than $100 right now.

[bevills1]

Did you run "Disk Cleanup" which will free up some space, but a bigger hard drive is your best solution? Just a couple of days ago I saw a 750 GB for $120 and a 500 GB for $90 three days ago on http://bensbargains.net/ which has great prices from various vendors on all kinds of computer accessories and electronics.

[Seeker47]

I believe you need at least 15% (8GB)

Even with more, the penalty may be time. It took me about 5 hours to do a defrag run yesterday evening -- showing 40% free space, albeit on an older laptop with a slower, 20G hard drive. I'm sure much bigger drives go a lot faster, on my desktop machine.