A recurring question in the forums and in the comments to the guides to optimize the PC concerns the operation of defragmenting the hard disk, which is done automatically in Windows 7 and Windows 8. One might wonder if modern computers still need defragmentation, that is, that process of putting files in order to maintain high performance.
The word fragmentation, relative to the files of a computer, means that the same file, since it does not find a continuous space, a sector on the disk, in which to position itself, is divided into various parts.
You can imagine a disc as a library and files as books with files: if a book does not fit completely into a space and if the other books cannot be moved from where they are, it is divided by placing a file on one side and the others on the other.
If the files are fragmented, however, their loading is slower because the computer has to look for every part of it on the disk.
Defragmentation is the procedure for moving files in an orderly manner, bringing the various parts of the files close together.
Fragmentation, today, is no longer the problem of 20 years ago, when hard drives were slow and the size of the processor memory reduced.
Now hard drives are very fast, fast processors and NTFS disks are larger than any sector where files are located, so that more data is contiguous.
Operating systems have also become smarter: a modern operating system is able to see with a non-random arrangement of files in sectors and functions such as prefetching to put data in sectors that are always close to each other.
On a recent computer, defragmentazone still has its utility, but you can safely do it no more than once a year .
On a PC with a limited capacity disk, with little space and almost always full, it is better to do the defragmentation even once a month.
If you are using Windows XP, defragmentation is worth planning (see how to plan maintenance operations in Windows)
In Windows 7 and Windows 8 defragmentation is scheduled automatically so you really don't need to start it manually or even use external programs.
Fragmentation, in theory, is not a problem only for Windows because all file systems are fragmented, including Linux systems.
However, as Linux is designed, the filesystem, especially ext3, keeps fragmentation to a minimum, keeping all blocks of files close, even if they cannot be written in consecutive sectors.
Therefore there is no need to worry about fragmentation on a Linux computer.
A separate discussion must be made for SSD disks that have no moving parts and quickly read data in any position they are.
Defragmentation, being a process that reads and writes data to move files, ruins and wears SSD disks and flash memory, so it should never be done.
If you are using Windows 7 or Windows 8 on a computer with an SSD disk, you should note that Microsoft has predicted that automatic defragmentation scheduling will exclude partitions on SSD disks.
In the guide on how to keep the SSD fast and make it last longer, there are all the necessary instructions also on how to check that automatic defragmentation is disabled.
I want to say that using an ancient Windows XP system on a computer with SSD disk does not bring any benefit to the overall speed of the system.
There are also some better programs to defragment the disk, but unless you are still using Windows XP, they can now be considered superfluous.
Summarizing the answer to the question is :
- Windows PC with SSD disk : Never defragment.
- Windows 7, Vista and Windows 8 have defragmentation as an automatically scheduled task and you don't need to worry about it
- Windows XP requires prompts to manually start defragmentation, every month or two or even once a year, depending on the size of the hard disk.
