Reduced Instruction Set Computer (RISC)

What is RISC (Reduced Instruction Set Computer)?

RISC, or Reduced Instruction Set Computer, was developed and launched by IBM in 1980. This is a specific type of architecture that needs fewer instruction sets to function.

Technically, the reduced instruction sets of the architecture allow the processors to run at a higher speed. Ideally, the compilers for the RISC hardware generate various RISC instructions.

Understanding RISC (Reduced Instruction Set Computer)

What is RISC (Reduced Instruction Set Computer)

Reduced Instruction Set Computer refers to those processors that have fewer instructions which help them to operate at a higher speed or perform more MIPS, a short for Millions of Instructions Per Second.

Typically, the concept of RISC has resulted in more thoughtful designs of processors. Some of the most significant design considerations that it has led to are:

The answers to these have led to better processors with better designs that have offered higher performance benefits.

It has also offered some other significant benefits related to their design and development. These are:

There are basically five design principles followed in developing an RISC. These are:

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Also, the higher-level language compilers can generate more efficient codes in a large number because they now have to use the smaller set of instructions found in a RISC.

Why is RISC Used?

The most significant reason to use RISC is that it offers a much higher and faster performance, increasing its performance per watt ratio, which is typically useful for the devices that run on batteries where energy efficiency is vital.

Some other reasons to use it so extensively include, but are not limited to the following:

All these result in increased performance, which is why RISC is considered to be an efficient CPU architecture technology existing today. It is used extensively because it can offer more with less in quick time, and also allows others to do the same.

What are RISC Examples?

One of the most common examples of RISC is the ARM processors, among a host of others, that are used extensively in smaller mobile devices.

Ideally, all modern CPUs use RISC architecture in some way or the other, which is mainly due to the progression of CPU architectures from 8 bits to 16 bits to 32 bits and higher.

Some other examples of processors that have some elements of RISC architecture in them include:

What Devices Use RISC?

RISC microprocessors are most commonly used in a variety of electronic devices, including smartphones, laptop computers, desktop computers, gaming consoles, tablets, and a large number of intelligent devices.

Typically, the use of RISC architectures is found on the following platforms.

Low-end, low-power, and low-cost embedded systems, Android based systems, as well as mobile systems such as:

The IBM PowerPC is used in gaming consoles such as:

The MIPS line is used in devices such as:

Apart from the above, different other variants are used in different devices such as:

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Several workstations, servers, as well as supercomputers also used different varieties and models of RISC-based microprocessors from the different manufacturers mentioned earlier.

What are the Main Properties of RISC?

The most significant property of the RISC is the fewer number of instruction sets in its architecture. These are much more simplified and smaller, which makes them less complicated.

It also includes register-to-register operations. This means that:

Some other features of the RISC processor architecture include:

Also, the number of addressing modes and transistors committed to the core logic is less due to the simpler addressing of all instructions.

Why is RISC Faster?

Typically, in the Reduced Instruction Set Computer, the instructions are fewer in number, just as its name signifies, which is the primary reason for it to operate at a high speed.

Ideally, every type of instruction that a computer performs needs additional circuitry and transistors.

This additional set of computer instructions makes the processor more complicated, which, in turn, reduces the speed of operation.

In contrast, the RISC processors come with several transistors that increase their speed, which helps them in using the simpler and limited number of instruction sets far more quickly.

This helps in streamlining data processing which accelerates its processing power with the use of a minimum number of instructions stored in the processor permanently.

Is RISC an Operating System?

RISC OS is a computer operating system that typically runs on ARM chipsets. It was designed originally by Acorn Computers Ltd. in Cambridge, England, and was introduced in 1987 to be used in the Archimedes line of personal computers.

Some of the useful features of this operating system are as follows:

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This operating system is worth using due to its increased usability, which eases the execution of all basic tasks. The features that add to its usability are:

There are a lot of bundled applications in this operating system that help the user get more artistic, allowing the creation of more scalable images, and a popular writer package to handle text and graphics more easily.

Other items included in it are:

Most of the operating areas are better covered in this OS, such as PCloud, which allows easy transferring of files.

You can also use this operating system to program in C, Python, Lua, and a few other languages. However, connectivity support is an issue due to the absence of good web browsers.

All these features make using RISC OS both a pleasure and a struggle. It is not highly likely to replace Windows or Mac completely but is still worth a try due to the pleasant GUI, which is not as interfering or heavyweight as the others.

However, with the development of RISC V, things will surely improve with better hardware support.

Are Intel Chips RISC?

Ideally, Intel x86 does not have a RISC engine but typically uses the x86 instruction set architecture for decoding and execution schemes, mapping the instructions onto machine operations, sequencing them for complex instructions, and finding a way through.

However, Intel joining forces with RISC V CPU Group has raised new speculations. It seems that Intel sees the future in x86, ARM, and RISC-V, all of which will play a major role in the CPU industry.

In fact, Intel has already been making an increasing demand for additional RISC-V chip offerings and Intellectual Property.

In addition to that, Intel has also announced and created a billion-dollar fund to support foundry startups that will prioritize investments in:

It has also shown initiatives in sponsoring development platforms for open-source software that will cater to all three major chip ISAs.

RISC-V provides open modular building blocks, which help in expanding its ecosystem and drive large-scale commercialization.

In short, Intel is already trying out this game-changer that can become a major chip power in the near future, which is why it has already offered a few RISC-V chips such as the Nios V processors.

Questions & Answers:

Does Windows Use RISC?

Well, several operating systems, including Windows and a few other NixOS flavors have moved to both RISC and CISC.

The Windows 10 IOT, Windows RT, and Windows Phone 7, 8, and 10 also run on RISC hardware.

Is the Apple M1 a RISC Processor?

Yes, the Apple M1 chips are RISC since they are based on the ARM architecture, which itself is a Reduced Instruction Set Computer processor.

Why Does Apple Use RISC?

The main reason that Apple is keen on using RISC is that the architecture provides the designers of processors with simpler and fewer instructions.

It may do less, but it can do it more quickly, adding to the performance improvements.


As you can see from this article, Reduced Instruction Set Architecture is quite useful to enhance the performance level and speed of a processor due to its simple encoding and fixed-length instructions.

The main objective of this design is to simplify the process of fetching, decoding, and issuing logic considerably.