Next important feature is the RAM (Random Access Memory). What is a computer RAM? The RAM or the Random Access Memory of your computer, is the primary memory of your computer. No doubt there are cache memories available, which are accessed by the processor before the RAM, but then, it is still attributed as the primary memory of any computer. Every program or application that runs in the computer, has to be first loaded on the RAM, before it can be accessed by the CPU, or in other words, before the processing starts. Even when a computer boots up, it is the BIOS routines which, when loaded onto the RAM, starts up the computer. It is a volatile memory, that is, it doesn't store data permanently. Once the power is cut off, there is nothing on the RAM anymore. But then, without a good size of RAM, your computer will not be able to function properly. Just as in the case of processors, there are a variety of RAMs to choose from the market too. DDR2 and DDR3 are among the most common choices. Again, you need to get the proper reviews between the two. DDR3 has, no doubt, got higher frequency ratings, but at the same time, the latency also increases on using DDR2. Thus, you need to make a choice of your own. The size of your RAM is chiefly responsible for the execution of your applications. Hence, take a RAM of a proper size that is sufficient to handle all your operations. If you want to learn a simulator on your laptop, then you are probably in need of a RAM somewhere around 2 GB. The size of the RAM is in fact, one of the primary requirements of operating systems and various other applications.