Gurvansh said..
This is important to know that how much Ram (Memory) your computer Has and how much it is using. Because it determines what programs you can run on your machine. It also allows you to run more programs at one time. According to capacity of your RAM you can do work on large amounts of data. Actually, this is totally depends that which Operating System you are using for you PC. Every Operating system has it’s own setting that how it show and use Memory.
You can find that out how much RAM you have by right-clicking the My Computer icon and selecting "Properties..." if you are using Windows. This will open the System Properties window and you can view the amount of physical memory installed under the General tab. You can find out how much memory your computer is currently using by right-clicking anywhere in the open space of the Taskbar and selecting "Task Manager." Then click the Performance tab of the window that opens and you will be able to view your memory usage.
If you are using Mac OS X, you can see you much RAM is installed in your computer by choosing "About This Mac" from the Apple menu. This is located in the far upper left-hand corner of the screen. To find out how much memory is being used, open the Activity Monitor program, located in the Utilities folder (within the Applications folder). Then click the System Memory button near the bottom of the window to see how much memory your system is currently using.