There is one main difference between a RAM and ROM chip. A RAM chip is volatile and needs a constant source of power to hold information. When power is turned off or is lost, a RAM chip will lose all the information stored on it. In contrast, a ROM chip is non-volatile and does not need a constant source of power to keep information stored in it.
Other differences between a RAM and a ROM chip include:
A RAM chip is used in the ordinary computer operations after starting up and loading the computer operating system, whereas a ROM chip is primarily used in the computer start up processes.
The process of writing data on a RAM chip is faster than writing on a ROM chip
Typically, a ROM chip only stores few megabytes of data, up to four megabytes or more per chip. A RAM chip can store numerous gigabytes of data, up to 16 gigabytes or more per chip.
In the computer, a good example of ROM is the computer BIOS, a chip that keeps the programming required to begin the first computer start up process. Some of the most common examples of RAM are RIMM, DIMM, SIMM, SOO-RIMM and SO-DIMM.
References
Computer Science with Myung 