What exactly does the Disk Defragmenter do?

It basically frees up megabytes.

As files are created and deleted on your hard drive, the nice organization of files each having their own uninterrupted sections of disk space starts to break up, and newer files end up spread around into several pieces on different sections of the disk. The operating system hides this from you, but it can mean that it takes longer to load the file. So what defragmenting does is move all the files around again so that they aren't scattered around, instead each file is now back to one single section of the hard disk, instead of being scattered around in several pieces. But on newer computers, defragmenting really doesn't make much difference in speed, because hard drives are so fast, and because operating systems are better at avoiding some fragmenting to begin with. I really have not seen a computer get noticeably slow due to fragmenting for probably 10 years at least.

Defragmentation makes the drive faster by reorganizing pieces of files and the entire files themselves on the hard drive, in a contiguous and optimized manner. Reading contiguous files is much faster than reading fragmented files. First do a disk cleanup. Right click the drive in My Computer, choose Properties and Disk cleanup. Delete the temp files, temporary internet files, empty the recycle bin etc. Don't compress the drive contents. Then you can defrag. I never liked the in-built Windows defragger; instead I use Diskeeper. Head over to http://www.diskeeper.com and download the free trial version of Diskeeper 2009. It's the best defragger for Windows and defrags everything including large files and system files, even with low free space. Install Diskeeper, turn on the auto defrag mode and dont worry about defrag again! Diskeeper will do everything in the background automatically, and you can use your computer as usual.

The Disk defragmenter puts back files that get fragmented (which happens in the process of adding/deleting/editing files) back together in a sequential order in order to speed up data access. This means files and programs and will open without lags and it prevents slowdowns caused by fragmentation.Among the defragmenters I have tried, I have found Diskeeper to be the most efficient. Its also very easy to use as it can be set to defrag automatically in the background, has a nice GUI and defrags system files. Try the 30 day trial if you wish http://www.diskeeper.com/defrag.aspx

Think of it like this. You have a big circle (disk). when you install programs, it writes the data in random spots on the disk. So the data is all distorted. When you do a disk deframenter, it takes all the data, and puts it all in one big clump. That means the computer doesnt have to search all around the disk trying to find the data. So lets say you download crysis the computer game, the computer will write some files on the north part of the disc, maybe some on the south, maybe south west part of the disk. The data is all over the place!! So when you do disk de fragmentation, it takes the data in the and puts it all in the one big clump. that way the computer doesnt have to look for it! questions? [email protected]

Think of it this way, a hard drive is like a brick house made up of data. As data is deleted it leaves gaps and spaces in the drive, so when the the disc is read it also has to waste time going over these empty gaps. A defragmenter removes these gaps and speeds up you PC's performance...supposedly. Read this article and look at the results. In this article it is shown defragmentation does very little to improve boot and shut down times, and sometimes even slows it down. http://www.maximumpc.com/article/the_disk_defrag_difference

It compacts fragmented or scattered files together. It's very helpful if you run it on a regular basis.