PC Components

How Many Transistors Are in a CPU?

Cpu Transistor

When it comes to computer circuitry, transistors are the fundamental building block. Transistors act like a switch that helps to allow or prevent the flow of current to flow through. Because of the complexity of most CPUs today, the number of transistors varies. But just how many transistors are in a CPU? 

Quick Answer

In a single modern CPU, there can be hundreds of millions, if not billions, of transistors. For example, the Apple MI 2020 CPU has up to 16 billion transistors; the AMD Ryzen 9 3900X 2019 has up to 9.89 billion transistors, while the AMD Epyc Rome 2019 has up to 39.54 billion transistors. 

The higher the transistor count on a CPU, the better the technology, which means a better experience. There are a number of factors that determine the number of transistors you’d find on a CPU. Keep reading to find out more about the transistor count on a CPU. 

What Determines the Number of Transistors in a CPU? 

The function of a CPU can largely be categorized into two main parts: fetch and decode data from memory and execute instructions. To perform these instructions, the CPU requires a certain number of transistors. The more transistors, the more processes the CPU can perform, thus making it better. Below are some factors that affect the number of transistors on the CPU. 

Factor #1: Architecture 

The architecture of a CPU refers to the type of instruction and how the CPU processes instructions. In today’s environment, there are two common processor architectures: the 64-bit (AMD64, IA64, and x86) and the 32-bit (x64). So, depending on which of these architectures comes with your CPU, the number of transistors on it will also vary. The reason for this is that the architecture of some CPUs is better at handling certain types of tasks than others. In other words, the 64-bit CPU architecture has more transistors and can process larger chunks of data than its 32-bit counterpart.   

Factor #2: Number of Cores 

Another factor influencing the number of transistors on a CPU is the number of cores on the processor. The core of a CPU is the part that receives instructions and performs operations. And to perform this, it requires transistors – lots of them. A CPU can have a single core or multiple cores. A CPU with two cores is called a dual-core, while one with four cores is a quad-core, and so on. As such, the more the number of cores on the CPU, the more transistors available, and the faster the CPU will be. 

Factor #3: TDP 

TDP or thermal design power of a CPU is the amount of power it uses under the max load theoretically. The more load the processor uses, the more heat it generates. Hence, computer manufacturers must design a cooling system to dissipate the heat under any workload. The transistors on the CPU also control this system. If the CPU performs a lot of work, it needs a better cooling system – hence more transistors – to prevent overheating

Factor #4: Clock Speed 

Clock speed is another factor that influences the transistor count on a processor. Clock speed refers to the number of processes a CPU performs per second. The clock speed of processors is measured in GHz, while some older models of CPU are measured in MHz.

So, if you see a processor with a clock speed of 2.0 GHz, it means it performs 2 billion processes per second. The higher the processor’s clock speed, the more processes it can perform. And for a processor to have a high clock speed, it has more transistors. Hence, a higher clock speed means more transistors, and a lower clock speed means fewer transistors. 

Factor #5: Manufacturing Process 

The manufacturing processes used by the manufacturer can influence the number of transistors on a CPU. Not all manufacturers have the advanced technology to put more transistors on a single CPU. Increasing the number of transistors on a single core will increase the cost of producing it. Hence, not many manufacturers are thrilled to put that many transistors on a CPU to make it more affordable for users to purchase. As long as the CPU performs what is needed, manufacturers don’t seem too bothered with increasing the number significantly. 

Factor #6: Other Factors 

Other factors can influence the transistor count on a CPU. For example, a GPU’s existence can significantly increase the number of transistors on the CPU. While dedicated graphics cards are becoming the norm, integrated graphics are not outdated. If a CPU had an integrated graphics processor, it would increase the number of transistor manufacturers that would have to input into the CPU. 

Key Takeaway

Transistors have a wide range of applications and are not only used in the CPUs of computers.


Knowing the number of transistors on a CPU is somewhat vague and transparent. Today many CPUs are made of billions of transistors. So, rather than focusing on how many millions or billions of transistors are on a CPU, being more concerned with what the device can do is more valuable. Hence, the CPU specifications, such as the clock speed, number of cores, and cache size, better gauge great performance. 

Frequently Asked Questions 

What is the size of transistors on a CPU? 

Considering the minute size of modern CPUs, how is it that transistors can hold billions of transistors? This is possible because the transistors on CPUs today are smaller than you might imagine. An average transistor on a CPU is only about 14 nanometers across. To put this in a better perspective, transistors in a CPU are about 14 times wider than a DNA molecule

How are transistors on the CPU manufactured? 

Transistors in CPUs are manufactured by a complex computerized method known as lithography. Because of how minute they are, they are printed on a silicon wafer under extreme ultraviolet light. 

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