How Does A CPU Processor Work? A Guide to Choosing Intel or AMD

The central processing unit (CPU) is the command center of your computer, responsible for coordinating almost every operation. Understanding how CPUs work and their impact on overall performance is essential when upgrading or replacing your PC.

Intel has long been the leading name in CPU manufacturing, and its processors are known for their longevity. But in 2022, AMD managed to surpass the long-standing industry giant in market cap. 

Which of the two processor brands is the better choice, and how can you make sure you pay the right price for a system that does what you need it to do? 

Below, we'll explain CPUs, how they work, the relationship between AMD and Intel, and why a refurbished system might be your best option. 

What is a CPU?

A CPU is simultaneously the brain and the beating heart of an electronic device. It manages the flow of data within a system while also executing commands from both hardware and software. 

Key components of a CPU include: 

• Control Unit: This handles instruction processing and data flow while also controlling other components of the CPU. 
• Register: A small, high-speed storage that acts as a CPU's "working memory." Different types of registers exist for operational data, instructions, and memory addresses. 
• Arithmetic Logic Unit (ALU): Executes both arithmetic and logical operations on data after receiving instructions from a register. 
• Memory Management Unit: Interfaces between the CPU and system memory (RAM), managing virtual address translation and memory access permissions. 
• Clock: Clock speed, measured in GHz, determines how many cycles the CPU can perform each second — but overall performance also depends on how much work is done per cycle (IPC).

There are also two main types of CPU architecture:

• x86/x64: Commonly used in servers, desktop computers, and laptops. Examples include Intel Core i3, i5, i7, and Xeon
• ARM: Built on reduced instruction set computing (RISC) architecture. Typically used in embedded systems and smartphones, but is starting to see some use in servers and desktop computers.

How Does a CPU Work? 

A CPU operates within the framework of cycles set by its clock. Each cycle consists of three steps directed by the program counter — a specialized register that tracks the memory addresses of upcoming instructions. 

Fetch

The CPU fetches instructions from memory, then its control unit interprets those instructions and identifies the required operation.

Decode

The CPU decodes the fetched instruction using its control unit. This means it breaks down what needs to happen—whether it’s a math operation, data movement, or a logical decision.

Execute

Once decoded, the CPU executes the instruction. If it's a math problem or comparison, it uses the Arithmetic Logic Unit (ALU). If it needs to move data, it interacts with the memory or other components.

Why are CPUs Important?

CPUs make computing possible in the first place, making them essential to the functionality of any digital device. Without them, running operating systems or applications wouldn't be possible.

Understanding CPU Performance

CPU performance is primarily determined by how efficiently it can process and execute instructions. While clock speed plays a role, modern CPUs are best evaluated by a combination of instructions per cycle (IPC) and other architectural and hardware-based features.

Several key factors impact a CPU's real-world performance:

• Core Count: More cores allow the CPU to handle multiple tasks simultaneously (parallel processing), which improves performance in multi-threaded applications like video editing or 3D rendering.
  
• Simultaneous Multithreading (SMT): Also known as hyper-threading (on Intel CPUs), this allows each core to process multiple threads at once, improving multitasking and workload efficiency.
  
• Cache Size: A larger CPU cache (L1, L2, and L3) helps reduce the need to access slower system RAM, speeding up repeated data access and boosting overall performance.
  
• Clock Speed (GHz): This represents how many cycles a CPU can perform per second. While higher clock speeds can mean faster performance, they must be considered alongside IPC for a more accurate comparison.
• CPU Architecture: The design and efficiency of the processor's microarchitecture (e.g., AMD Zen 4 vs Intel Raptor Lake) significantly influence performance by improving IPC, energy efficiency, and heat management.

A Brief History of Intel and AMD

Intel and Advanced Micro Devices (AMD) have long defined the evolution of computer hardware, starting with the former's invention of the first microprocessor in the 1970s. Although it was founded around the same time, AMD wouldn't become a significant competitor for Intel until the 1990s. Since then, the ongoing rivalry between the two companies has been an ongoing source of innovation for computer hardware.

For much of this time, AMD was basically playing catch-up to Intel. This changed in 2017 with the launch of AMD's Zen architecture. Processor series built on this architecture include:

• AMD Ryzen 3: Budget-friendly processors best for casual gaming and distributed work.
• AMD Ryzen 5:  Mid-range processors with a decent balance of performance and price.
• AMD Ryzen 7: Intended for heavy multitasking, gaming, video editing, and other high-performance activities. 

In 2022, AMD started outperforming Intel for the first time due to a combination of a new chip design approach, its Zen architecture's success, better performance per dollar, and a partnership with Taiwan Semiconductor Manufacturing Company (TSMC). 

AMD's focus on high-performance computing and the fact that Intel had been suffering considerable execution issues and manufacturing delays also contributed heavily to AMD's newfound market dominance. With all that said, Intel is far from defunct. 

The company is still one of the largest hardware manufacturers in the world, and it's been slowly catching up to AMD again in recent years. 

Intel CPUs 

Intel is the historical titan of the CPU market. Although AMD has eclipsed Intel in recent years, they're still a force to be reckoned with, and their X86 architecture is still widely and heavily used. Intel has remained a dominant force on the market for so many years, which means their hardware tends to have broader compatibility than many other CPUs. 

Newer Intel processor generations are built with hybrid architecture to improve both performance and efficiency. Intel also owns and operates the entirety of its manufacturing infrastructure. This has allowed the company to become a leader in advanced manufacturing processes.

Compared to AMD, Intel CPUs tend to have better single-core performance. Intel processors also support instruction set extensions for specific workloads and tasks, such as graphics, video processing, and 256-bit vector processing. 

For graphics, Intel CPUs are equipped with Iris Xe integrated GPUs, which are well-suited for light gaming and creative tasks but tend to struggle with more performance-intensive software. 

Lastly, Intel CPUs generally have higher clock speeds compared to AMD, though this gap has been growing smaller.  Other recent innovations include artificial intelligence and 3D-stacked-on-die memory. 

AMD CPUs

Although AMD doesn't have the established pedigree of Intel, what it lacks in name recognition it makes up for with its excellent multi-threaded performance. In addition to being more power-efficient than Intel, AMD CPUs also tend to provide better performance per dollar, particularly budget and midrange options. 

Another area where AMD has excelled is its design approach. Instead of manufacturing integrated circuits as consolidated units, the company breaks them into modular components called chiplets. This style of manufacturing is both more efficient and cost-effective than traditional methods — meaning it more than likely contributes to the price point of AMD CPUs. 

AMD CPUs with an Accelerated Processing Unit (APU) feature AMD Radeon Vega integrated graphics, outperforming Intel Xe but still struggling with more graphic-intensive tasks. 

AMD's current product roadmap focuses on improved multi-core efficiency and performance. 

The Benefit of Buying Refurbished

If you're in the market for a PC, it can be tempting to purchase a brand-new machine. But it might not always be the right choice. Depending on your use case, budget, and needs, buying refurbished laptops or desktops may be best.

There are a few reasons at play here.

Because factory-new systems typically aren't tested, there's a chance you'll receive a defective model. On the other hand, refurbished machines are individually repaired and tested by a trained technician. They also ship with warranties similar to what you'd receive with a new system. 

Cost is another huge benefit. Refurbished machines offer the same level of performance and reliability as factory new machines at a fraction of the price. 

Lastly, refurbished devices are more environmentally sustainable overall. Purchasing the refurbished item means you're preventing it from becoming e-waste. It also means reduced manufacturing and supply chain demand, both of which contribute heavily to climate change. 

Which CPU is Better? 

Whether you're buying refurbished laptops or desktops, finding the right CPU is crucial. But how can you tell? And which should you choose? 

Intel and AMD are both market leaders, and both companies offer a range of high-quality CPUs. Neither is better than the other. The option you choose ultimately comes down to a combination of personal preference and computing needs. 

If you know you'll be working with artificial intelligence, purchasing a system with a newer-generation Intel CPU is probably the right call. On the other hand, if you're using your PC for video editing, streaming, or another resource-intensive task, AMD might be the better choice. 

In other words, it comes down to finding your best fit. 

Choose the processor that makes the most sense for you! Shop Refurb.io today!