CISC and RISC

CISC and RISC are Instruction Set Infrastructures (ISA), sets of syntaxic rules built at the core of our processors, which define how and which instructions are executed, and their level of complexity. Components of on ISA include instructions, registers, memory addresses, and data types.

CISC

Complex Instruction Set Computer is an ISA used in most Intel and AMD computers. It favors longer and more complicated instructions, by combining simpler ones together.

Even though it executes more complex instructions, those take more clock cycles, and more power is consumed for each of them

RISC

Reduced Instruction Set Computer is an ISA used on mobiles and Macs. It favors shorter instructions, that take an entire clock cycle, hence resulting in a large number of instructions per program. It supports around 200 instructions, compared to CISC's 1500-ish. The fact that all instructions take exactly one clock-cycle makes the program much more optimized and its energy consumption far lower.