These four major parts of the computer are all working well together in order to create processes that will make people’s work faster. For example, the CPU is known to be the brain of the computer. Without this, the whole system will not work.
The memory is also important. Imagine having to do work and not having enough space to do your work. This can make things hard for you to do. The input and the output devices are also important because they can make the things that you are going to do with your computer easier to do and accomplish.
Unless you're talking of ancestral computers, you'll need a board that interconnects the various devices you use in your computer. if you think main memory (RAM) isn't essential, please remove the DRAM modules of your computer and try to boot your computer up. (If your computer uses Static RAM I'm stealing your PC muahuahuahua!).