The basic purpose of cache memory is to store program instructions that are frequently re-referenced by software during operation.
Fast access to these instructions increases the overall speed of the software program.
Cache memory is not associated with ROM, rather it is called as CPU or Random access memory which a computer microprocessor can access more quickly than a regular RAM.
This memory is typically integrated directly with the CPU chip or placed on a separate chip that has a separate bus interconnect with the CPU.