The basic thumb rule is that the requirement of memory for a computer is determined mainly by its usage and the software that is going to be used in the computer. The minimum and the requirements that are recommended have to be taken into consideration depending on its use. Thus the RAM to be installed should be sufficient enough to run the computer efficiently. The running of system will differ according to the capacity of the memory. For example, with 1 GB memory, the system will give the minimum function and 2GB will be optimum for almost all the systems and with the installation of 4GB, it is definite that a smooth sail can be obtained.

The above ranges that are given are generalized based on the general tasks of the computers. It is advisable to completely look into the requirements and the software going to be utilized before making any ultimate decision on the memory chip installation. The memory requirement will not be the same for all the computers as some computers will have more responsibilities and hence need more memory than the other computers.

A 4GB memory can be installed in a computer which has got a 64 bit operating system that will provide smooth function. Thus the performance of the system relies on the type of the memory installed in it. The two memories that are currently used in the computers are DDR2 and DDR3.

Utmost care has to given on purchase of new computers with regard to the memory. The old version of the memory RDRAN and SDRAM should be avoided in the new computers as they are very old fashioned and will not suit the recently developed computers. The memory capacity also depends on the speed of the RAM that is installed on the computers. Some of the RAM and their memory speed are given below for immediate reference in the order of slow to fast.

DDR2 400 MHz, DDR2 533 MHz , DDR2 667 MHz , DDR3 800 MHz , DDR2 800 MHz , DDR3 1066 MHz , DDR3 1333 MHz , DDR3 1600 MHz .

The speed of the above memories are relatively compared to the bandwidths of all the types of memories at the given clock speed when it is compared with the other. A computer can use only one type of memory once and the same has to be used for comparing when two computers have the same CPU. The other memory standard available is JDEC.

The memory of a system is also expandable which can be done depending on the support that particular system can extend. Many of the desktop systems will have provision for four memory slots that are installed in two's. Now the updated version systems do have with threes.