Actually, cache memory is made up of SRAM which is different from regular memory, DRAM.

All RAM must be constantly refreshed by electricity so it can "remember" its data. SRAM chips do not have to be refreshed as often as DRAM chips. This means SRAM works faster. They are also more expensive.

Beginning with the 486 CPU, Intel began building cache right into the CPU. So cache can be classified into two different categories: internal cache which is inside the CPU, and external cache which is outside the CPU.