If your computer is running one of the versions of Windows OS, then in the root directory of the disk on which the system is installed there is a file of considerable size called pagefile.sys. It is called a "swap file" or swap file, and the operating system needs it, mainly to work with RAM.
Let's say you work long and hard in Word or Photoshop on a document, and then it's time for a few tens of minutes to get distracted from a difficult task and relax. In the absence of a boss nearby, the most suitable way is to dunk a couple of dozen monsters in a video game. When you run it without closing the documents you were working on, the operating system will have to take care of freeing up RAM for a new task. To do this, it will move some areas (pages) to the paging file, and when you return to work again, the OS will do the opposite procedure - it reads the necessary fragments from the swap file into RAM. It follows from this algorithm of using virtual memory that the larger the amount of "RAM" installed in the computer, the less frequently the paging file is used by the system and the faster the computer works. This is because the speed of writing and reading to a hard disk is significantly inferior to similar operations with RAM in microchips.
When a new operating system is installed on a computer, it sets the size of this auxiliary file to the size of the existing RAM by default. However, if you are confident that your computer has more than enough RAM for your work, you can slightly increase the amount of space on your hard disk by reducing the size of the pagefile.sys file by several gigabytes. And if there is an obvious lack of RAM, you should do the opposite - increase the size of the swap file. This is not done "manually" - the corresponding settings are provided by the Windows manufacturer and are available in one of the sections of the "Control Panel" for an OS user with administrator rights. The sequence of steps for such operations is described on the Microsoft website - a link to the corresponding page of instructions for Windows 7 is given below.
