Computer processor, what it is and how it works

Interface with peripherals

One vital role of the CPU is to communicate with various peripherals, including the keyboard, mouse, and screen. It achieves this through a series of interfaces and external components that facilitate seamless communication. Additionally, the processor is equipped with interrupt mechanisms, allowing it to pause its current tasks temporarily to respond to simple requests, such as moving the mouse or pressing a key on the keyboard. Understanding these fundamental elements will help you gain a clearer grasp of your computer’s central processing unit.

Understanding the specifications of a computer processor

When browsing web pages for processor purchases or checking computer specifications, a slew of acronyms and technical terms can be overwhelming, especially for those without prior experience in this realm. Don’t fret or feel discouraged; you’re not alone. Even the person writing this very text has no knowledge of mechanics and couldn’t differentiate between a diesel engine and a gasoline engine. Seriously, no exaggeration here! So, I completely empathize with those users who find themselves wearing a poker face when confronted with processor specifications.

What is the number of cores of a processor?

A processor core is, in essence, a processor itself. In modern processors, we find several cores integrated onto a single chip. Although physically we have one chip containing all these cores, we often refer to them singularly as processors or CPUs, hence the singular name.

In the past, performance improvements were achieved by increasing the processor’s clock speed with a single core. However, this approach eventually reached its limits, and the solution was to incorporate multiple cores to enhance performance further. Each core can be likened to a distinct worker that collaborates with the others, collectively boosting the processor’s capabilities. Therefore, an 8-core processor means there are 8 individual processors working in unison on one chip.

Having more cores means a more powerful processor, but it also increases the cost. As technology advances, we witness the ongoing development of multi-core processors, driving computing performance to new heights, albeit at different price points depending on the number of cores.

What does it mean for a processor to be multithreaded?

An execution thread refers to a program that the processor must carry out, essentially a set of instructions guiding its actions. In an ideal world, this process would run smoothly, but reality often differs, and sometimes a program halts temporarily due to insufficient information, causing what is commonly referred to as “bubbles.”

The concept of multithreading aims to enhance processor efficiency by allowing it to execute another program or thread while waiting for the first process to resume. This means that during bubble periods, the CPU remains productive, effectively simulating a second core by duplicating a significant portion of the processor circuitry. It creates the illusion of a virtual second core, primarily through the control unit, though not a complete second core in itself.

To illustrate, a 16-core CPU with only a single execution thread can outperform an 8-core CPU with 16 execution threads. The key lies in maximizing the CPU’s potential during idle moments, elevating overall performance. Multithreading offers an ingenious approach to optimize processor capabilities, driving computing power to higher levels.

What is base clock speed?

Clock speed refers to the time it takes for all the internal components of a processor to complete a basic operation. Let’s imagine a scenario where we can only make one movement to the beat of a constant signal, just like in a children’s game where we move with each clap. In a processor, the internal components work similarly, synchronizing their operations to a specific rhythm.

In modern processors, clock speed is measured in GHz, which stands for one billion Hz. This measurement is used for marketing purposes because it is more relatable to people. For instance, saying a CPU has a clock speed of 4 GHz is more straightforward and indicates greater power compared to a CPU with 3.8 GHz. Using units of time like seconds or minutes could create confusion and be less intuitive for end-users.

Moreover, when we mention the base clock speed, we are referring to the speed at which the processor primarily operates. However, processors can adjust their clock speeds depending on the workload, allowing for dynamic performance optimization. Clock speed plays a crucial role in determining the overall performance of a processor, and understanding its significance helps users make informed decisions when choosing hardware.

What is Boost or Turbo Clock Speed?

Newer processors often come equipped with a feature called “Boost” or “Turbo speed,” which represents a second clock speed that the processor can reach, and it’s significantly faster. This enhanced speed, however, comes at a cost: increased power consumption and higher chip temperatures. Consequently, the processor can only sustain this boosted speed for a brief period before reverting to its original speed.

The Boost or Turbo mode is typically activated during demanding tasks when the processor has a lot of work to handle. This allows the chip to quickly tackle the workload and then return to its standard speed, helping to balance performance and efficiency. It’s like a temporary burst of power to handle heavy tasks, ensuring optimal performance without compromising the overall stability and reliability of the processor.

What is the socket of a processor?

The processor socket serves as the connection point for the processor on the motherboard, providing all the necessary links for power supply and communication with other computer components. It enables the processor to interact with the graphics card, RAM memory, storage units (SSD or hard disk), and various peripherals.

It’s important to note that processor sockets are not universal, and each generation and brand of processors has its own unique socket. Consequently, when purchasing a processor, it can only be used on motherboards that have a matching socket. In other words, each processor has its preferred partner, so when building a custom computer, one must choose a compatible motherboard for the selected CPU.

However, this distinction does not apply to laptops. In the case of laptops, the processor is directly soldered to the motherboard, without an interchangeable socket. Laptops are typically sold as integrated units, not individual components, as they come pre-assembled by the manufacturer. Therefore, there is no option to replace the processor separately in laptops as you would in a desktop computer.

What is the processor in a PC?

A processor, also known as a CPU (Central Processing Unit), stands as the most crucial chip housed within our computers or PCs. Its primary function is to execute programs and govern user interactions with them. The term “processor” originates from its role in processing program instructions, which are expressed in binary code with values of 0s and 1s, enabling us to interact with various applications while using a computer.

In contemporary times, the CPU represents an extraordinarily intricate piece of engineering, consisting of billions of fundamental structures known as transistors. As technology progresses, these transistors are becoming smaller and more sophisticated, leading to substantial improvements in CPU performance. The evolution has allowed the integration of various functionalities, such as the memory controller, into the processor, a feat unimaginable in early CPUs from the 1980s that contained less than 100,000 transistors. Today, CPUs boast an astounding complexity, with some containing up to 10,000,000,000 transistors after four decades of advancements.

Given the extraordinary complexity of modern processors, it’s essential to understand their most fundamental components—the aspects shared across all CPUs, from the earliest models in the mid-70s to the latest powerhouses utilized in high-performance gaming PCs.

Basic anatomy of a processor

First and foremost, it’s essential to understand that a processor operates as a machine, performing a recurring task known as the instruction cycle. To keep things simple, here’s a basic description of the cycle:

1. The processor fetches an instruction. (Fetch)
2. The instruction is decoded to understand its meaning. (Decoding)
3. The processor executes the decoded instruction and produces a result. (Execute)
4. The cycle repeats, going back to step 1 for the next instruction.

This recursive process occurs in all CPUs, from the very first ones ever created to the most recent models available today. However, delving only into this aspect may not fully convey what a processor truly is. Hence, we will now provide a brief overview of the various components that constitute a processor, helping you gain a better understanding of its overall functionality.

Fetch

It is crucial to acknowledge that a processor cannot function without its corresponding RAM memory, which is another essential component of a computer, typically located on a separate chip. Therefore, one of the first components we require to assemble our computer is an interface with the external memory, allowing the processor to access and execute the stored binary code.

RAM memory is organized in a structured manner, and to facilitate smooth execution of programs, we need a component called a program counter. This counter plays a vital role in guiding the processor to the next instruction that needs execution. It becomes particularly significant as programs often contain conditional jumps, causing the processor to switch to a different location in memory based on specific conditions. The program counter ensures the processor follows the correct sequence of instructions and handles these jumps efficiently.

Decode

The previously discussed elements enable us to retrieve instructions from RAM, but these instructions are encoded in a specific manner, not just binary format but also involving their interpretation. To draw a parallel, consider two individuals who are familiar with the same alphabet, say a French and a German person; they may recognize the letters, but they won’t comprehend the language the other writes. In the world of processors, we refer to the language or dialect specific to each family of processors as the ISA (Instruction Set Architecture) along with its set of instructions and registers.

Therefore, to proceed with execution, we require a unit capable of decoding these instructions. Aptly named the “decoder,” this component allows the processor to discern the type of instruction it needs to execute. Once identified, the processor merely needs to send the instruction to the corresponding execution unit, responsible for resolving it. This task is facilitated by the “dispatch unit,” which efficiently manages the execution process.

Execute

Throughout the history of computer architecture, the term ALU (Arithmetic Logic Unit) has often been used to refer to execution units. However, it’s essential to recognize that the ALU is just one type of execution unit, and there are various other types. Let’s delve into some of these execution units:

1. Load/Store Unit: This unit manages memory access instructions, responsible for fetching data (read) from memory or updating data (write) in memory.

2. Branch Unit: The branch unit controls the flow of code by handling jump instructions. Its primary task involves modifying the value that stores the program counter, directing the processor to the appropriate instruction based on conditions.

3. ALU (Arithmetic Logic Unit): The ALU is tasked with executing mathematical calculations. There are different types of ALUs, ranging from those that handle whole numbers or decimals to those capable of executing the same instruction on multiple numbers simultaneously. The latter type is known as SIMD (Single Instruction, Multiple Data) units.

These various execution units work together harmoniously, enabling processors to perform a wide range of operations and computations, essential for efficient functioning and performance in modern computing tasks.

Memory inside the processor

Inside the processor, we find a series of memories designed to temporarily store data. This serves to alleviate the burden on the RAM memory and prevent the processor from being bogged down by excessive requests, which would otherwise slow down the system significantly.

There are two main types of internal memory in a CPU:

1. Cache Memory: Its primary role is to store a portion of the RAM, enabling the processor to access the code to be executed much faster. By keeping frequently used data close to the processor, cache memory significantly enhances its efficiency.

2. Registers: These are extremely small but fast memories utilized by different components of the processor to execute the recursive tasks mentioned in this article. Registers play a vital role in speeding up calculations and data processing within the CPU.

Understanding these fundamental concepts provides you with the basic knowledge of how your system’s CPU operates. These internal memories play a critical role in optimizing the processor’s performance and overall system responsiveness.