RAM stands for Random Access Memory; it is what the computer uses to run separate programs. In general, the more RAM your computer has, the faster individual programs will run, and the more programs you will be able to run at once.
Normally, when more than one program is running, the CPU allocates RAM according to each program's needs. If one of your programs is lagging, however, sometimes there are ways to increase the amount of memory allocated to that application.
Increase your pagefile. The pagefile is a section of the hard drive that is used as RAM by the processor and is also called Virtual Memory. Although it is not as fast as RAM because it is physically located on a hard drive, increasing it can sometimes increase program performance. To access it, open your Control Panel. Click "System," then "Advanced system settings," and then "Settings" in the "Performance" tab.
Increase the total amount of memory available by quitting any running programs that you aren't currently using. Although a program running in the background does not consume many resources, it can sometimes consume enough to make a difference in speed.
Open the Task Manager by hitting Ctrl-Alt-Del and quitting any running services that you don't need. Again, these services can use precious system resources that could be used for your program.
Increase the amount of maximum memory in the program itself. Some programs, such as many Adobe applications, allow you to specify the maximum amount of memory that program is allowed to use. Check the "Preferences" window for a memory usage setting, often found in the "Edit" menu.
Increase your computer's physical RAM. RAM chips are inexpensive, and are often the easiest way to upgrade an otherwise sluggish computer. To get the best performance, add the maximum amount of RAM that your motherboard can handle.
Don't increase your page file size to more than 1.5 times the amount of physical RAM installed in your computer, as this can lead to stability issues.