Upon purchasing a new computer you power it on and begin to work. It is at optimal speed and very little drag due to being the latest technology in hardware. About a year goes by and despite new faster technology in the spirit of Moore’s Law your system is running slower than when it was first purchased. During this year you have written many documents, uploaded movies, pictures and music. All at the same time you have removed some documents no longer needed or deleted the music you have outgrown among other files. You have added programs and deleted them a few months later.
another day you try to access them however you are jumping back and forth looking for the complete file which you separated or the file to begin with. Eventually you find your files but at a much slower speed than you did before when you purchased the desk. This is how fragmentation is on your hard drive. The reader is jumping back and forth trying to locate the files you request. It has to jump over bubbles left behind after you delete files and search the file and the related or associated files.
placed on a schedule. Routinely defragging your hard disk will keep your system running near purchased speed.
It would be nice if defragging was the only problem faced when your system begins to slow but there can be a number of things. Another is process load. Process load is when you run more than one program at a time. Some may not be seen or initiated by the user. They may be programs running in the process speed you can look into defragmentation or adding more RAM to help with the virtual memory.