- It is known as Reduced Instruction Set Computer.
- It is a type of microprocessor that has a limited number of instructions.
- They can execute their instructions very fast because instructions are very small and simple.
- RISC chips require fewer transistors which make them cheaper to design and produce.
- In RISC, the instruction set contains simple and basic instructions from which more complex instruction can be produced.
- Most instructions complete in one cycle, which allows the processor to handle many instructions at same time.
- In this instructions are register based and data transfer takes place from register to register.
- It is known as Complex Instruction Set Computer.
- It was first developed by Intel.
- It contains large number of complex instructions.
- In this instructions are not register based.
- Instructions cannot be completed in one machine cycle.
- Data transfer is from memory to memory.
- Micro programmed control unit is found in CISC.
- Also they have variable instruction formats.
|Architectural Characterstics||Complex Instruction Set Computer(CISC)||Reduced Instruction Set Computer(RISC)|
|Instruction size and format||Large set of instructions with variable formats (16-64 bits per instruction).||Small set of instructions with fixed format (32 bit).|
|Data transfer||Memory to memory.||Register to register.|
|CPU control||Most micro coded using control memory (ROM) but modern CISC use hardwired control.||Mostly hardwired without control memory.|
|Instruction type||Not register based instructions.||Register based instructions.|
|Memory access||More memory access.||Less memory access.|
|Clocks||Includes multi-clocks||Includes single clock|
|Instruction nature||Instructions are complex.||Instructions are reduced and simple.|