The hard drive of the computer holds all the computer programs and the RAM is what runs the various applications when you want to use them. You make a call via RAM to the hard drive and say, I want you to run Internet Explorer. The hard drive then accesses the data and hands it over to the RAM which assembles the pieces of information and makes the program operable. The size of the hard drive and the size of the RAM determines how fast your computer operates.
The first thought should go to how much RAM you have on your computer. If you're building an Egyptian pyramid with 10 workers its going to take a lot longer than if you had a million. That's why having sufficient RAM in your computer is important. Some of the programs on the hard drive contain pyramid-sized information and RAM, although it works in milliseconds, can only process so much information at a time. That's why you need more workers (RAM).
Virtual memory is like back-up ram on the hard drive. The hard drive allocates space to be used in much the same way as RAM but it slows down the computer. When you direct the computer to perform a function and the RAM is low, it jumps back to the hard drive to utilize virtual memory, which takes a little more time. You can manually allocate virtual memory on the hard drive yourself but it's usually a sign that you have too many programs and not enough RAM. Buying more RAM for your computer is much less expensive than it once was.
These steps are for Windows XP so it may be a little different for the operating system you are using but with a little fidgeting you should be able to figure it out. It's pretty simple, actually. Go to Start > Control Panel > System. Then click on "Settings" under the performance section. Go to the advanced tab, click "Change" under Virtual Memory and select the drive where your files are located. It's usually the C: drive. You should have a prompt that allows a change in virtual memory, increase the value and click save.
There are two types of RAM. There are static RAM chips and dynamic RAM chips and they operate differently. Static RAM uses a completely different technology that takes more transistors and wiring. Because of the way it works it holds less memory for the size of the RAM chip. This makes it significantly faster than dynamic RAM but it also makes it significantly more expensive. The dynamic chip, is constantly refilling its chip brain with information as it is being used. The static chip holds the information, making it more readily available at a millisecond.