RISC vs. CISC Architectures

In contrast, CISC code often uses more complex instructions that can combine multiple operations into one.

For example, a single CISC instruction such as:

ADD X, Y

might load two numbers from memory, add them, and store the result back in memory (inside the variable whose address is A.) The computer will perform all of these actions as a consequence of calling just this one ADD.

Obviously, the instruction above will take multiple clock cycles to get completed.

While RISC code requires more lines, it allows for faster execution because each instruction is simpler and executes in a fixed time. On the other hand, CISC code reduces the number of instructions, but each instruction can take longer to decode and execute because of its complexity.