There was a time when a fragmented hard drive would cause your computer to noticeably slow down. File fragmentation is a natural byproduct of creating, storing, and interacting with your files. Data bits that make up your files get scattered to multiple non-contiguous sectors. Imagine a file cabinet containing your paper files. Fragmentation is like pieces of your paper file being cut up and stored in different folders, scattered throughout your file cabinet. It would certainly take much longer to pull a complete file if you had to locate and reassemble each piece. But modern hard drives are so fast and the caching built within them is so much larger compared to yesterdayís drives, that it is difficult for a user to perceive any performance difference before or after defragging a drive. You can find plenty of argument both for and against the importance of keeping your hard drives defragged. I believe it to still be beneficial, but I now do it no more than once per month. However, I also run it just prior to making an image backup of my hard drive in an effort to reduce the size of the backup image.
Fragmentation does occur in hard drives, and not just in Windows computers. Other operating systems cope with file fragmentation, but they handle it seamlessly without the user even being aware that it is in fact going on behind the scenes. It is interesting that, with Windows 7, Microsoft by default has Disk Defragmenter scheduled to check for fragmentation every night at 1:00 AM without the user even knowing of its operation. In all previous Windows operating systems, the user had to either manually run the program or use Task Scheduler to automatically start it to check the drive.
Now we have Solid State Drives (SSD) and USB Flash Drives (UFD). For the sake of simplicity, we will refer to both as flash drives. Should we defrag flash drives? The short answer is no. If you have a flash drive in your PC then you should be aware that using any conventional defrag program will shorten the life of the drive. Flash drives have no physical moving components such as a standard hard drive, and therefore cannot benefit from defragging. The cells in a flash drive have a limited life span. Their life is defined by a general number of read/write cycles to which they can be subjected. Defragging requires intensive reads and writes as it attempts to repair the fragmentation of files, which can much more quickly reduce the life span of the drive. Worse yet, flash storage does its own defrag maintenance and wear management so when we apply our customary defrag software, we not only use up the flash chipís read/write limit, but we also thwart the flash drives built in mechanisms for optimizing the drives lifespan.
If you are interested in Intelís take on the subject, click here
to go to Intelís FAQ section on Solid State Drives.