Difference between Main Memory, Cache Memory and Virtual Memory?

Answer 1

Main is the standard memory people think about. It provides lots of rapid speed, and expandable, memory.

Cache memory is special, and is optimized for the CPU, so it is the fastest, but ususally determined by the cpu, and typically you can't add any.

Virtual memory is needed in Windows when the real memory is all busy. I takes some of the hard drive and makes it into memory for processing. By far the slowest speed.