Acronyms are the tech world's favorite way to make exciting technology sound incredibly confusing. When hunting out a new PC or laptop, the specifications will mention the type of CPU you can expect to find in the shiny new device. Frustratingly, they almost always fail to tell you why that's so important.

When faced with decisions between AMD and Intel, dual or quad-core, and i3 vs. i7, it can be hard to tell the difference and why it matters. Knowing which is best for you can be difficult, but we're here to help you out.

What Is A CPU?

Graphical illustration of a CPU
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The Core Processing Unit (CPU) is often called the brains of the computer. It is one of several processing units but is arguably the most essential. The CPU performs calculations, actions, and runs programs.

In older computers, these functions were split across multiple processors. But, manufacturing and design improvements mean that the entire CPU can fit onto a single chip. This is why you'll sometimes hear CPUs referred to as microprocessors, too.

These smaller sizes have meant we can reduce computers' size to all-in-one devices and have thinner, lighter laptops. These powerful processors are also central to your smartphone's performance.

What Does a CPU Do?

There have been a lot of improvements over the years since the first CPUs came on the scene. Despite that, the primary function of the CPU has remained the same consisting of three steps; fetch, decode, and execute.

Fetch

Just as you may expect, fetching involves receiving an instruction. The instruction is represented as a series of numbers and is passed to the CPU from the RAM. Each instruction is only one small part of any operation, so the CPU needs to know which instruction comes next.

The current instruction address is held by a program counter (PC). The PC and instructions are then placed into an Instruction Register (IR). Subsequently, the PC length is increased to reference the next instruction's address.

Decode

Once an instruction is fetched and stored in the IR, the CPU passes the instruction to a circuit called the instruction decoder. This converts the instruction into signals to be passed through to other parts of the CPU for action.

Execute

In the final step, the decoded instructions are sent to the relevant parts of the CPU to be completed. The results are usually written to a CPU register, where later instructions can reference them. Think of it as essentially like the memory function on your calculator.

What Are Multi-Core CPUs?

Early computers would only have a single processor core, so the CPU was limited to processing one set of instructions at a time. This is why these older computers were relatively slow, and it was a time-consuming affair to process data.

Over the years, manufacturers pushed single-core CPUs to their limits, so they began looking for other ways to improve the processor's capabilities. This is why we now have multi-core processors, with phrases like dual-core, quad-core, and octa-core frequently adorning PC marketing material.

However, they aren't as complex as they first seem. For example, a dual-core processor is really just two separate CPUs on a single chip. Rather than redesigning the CPU entirely, the companies made improvements to the manufacturing process to improve performance.

More recently, processor designers found a way to further increase performance by making a single-core processor act as though it had two cores. This is known as hyper-threading and is common in most of the Intel Core range of CPUs.

Understanding CPU Specifications

Understanding how a CPU works is crucial, especially if you combine that with an awareness of the leading brands and ranges. However, there are many options with similar high-level specifications.

To help you compare models effectively, you can take some additional more detailed specifications into account. These will help you decide between CPUs when it comes time to invest in a new, modern processor for your computer.

Mobile vs. Desktop CPUs

Traditionally, computers were large, static, desktop electronic devices constantly powered by mains electricity. However, we now have laptops, smartphones, tablets, and smart home devices with CPUs more powerful than years-old PCs.

To achieve this switch to a more portable lifestyle, the devices use specifically designed mobile processors. These CPUs are optimized for power consumption and efficiency to extend your battery life as much as possible. Frustratingly, many manufacturers have named their mobile and desktop processors the same thing, but with different range numbers and suffixes.

Although there's no standard, generally, mobile processors are labeled 'U' for ultra-low power, 'HQ' for high-performance graphics, and 'HK' for performance graphics and overclocking. Similarly, desktop CPUs are appended with 'K' for overclocking and 'T' for optimized power consumption.

32 vs. 64-bit CPUs

Your processor doesn't get a constant flow of data. Instead, it receives the data in smaller chunks known as a word. The performance of the processor is limited by the number of bits in a word. Although 32-bit processors were first designed in the 1940s, they didn't become practical until much later.

By the 1990s, they were affordable enough to include in consumer electronics, and everyone assumed 32 bits would be relatively future-proof. However, as predicted by Moore's Law, technology continued improving, and soon, 32-bit processors were a limiting factor in hardware and software. As a result, they were gradually phased out in favor of 64-bit processors, the current worldwide standard.

CPU Thermal Power Design

The Thermal Power Design is a measure of maximum power in Watts your CPU will consume. While lower power consumption is clearly good for your electricity bills, it can have another surprising benefit; less heat.

CPU Socket Type

The CPU needs to be attached to the other components through the motherboard to make up a fully functioning computer. When choosing a CPU, you need to ensure that the CPU and motherboard socket types match.

L2/L3 Cache

The L2 and L3 cache is a speedy onboard memory for the CPU to use during processing. The more you have of it, the faster your CPU will perform.

Frequency

The frequency refers to the operating speed of the processor. Before multi-core processors, frequency was the most crucial performance metric between individual CPUs. Despite the addition of features, it is still a vital specification to take into account. Notably, a very fast dual-core CPU can outperform a slower quad-core CPU, for example.

The Brains of the Operation

The CPU is arguably the most crucial component of your computer. It performs all the tasks you associate with computers, and the other parts primarily exist to support the CPU. Despite following the same guiding principles for many decades, there have been notable improvements like adding multiple cores and the use of hyper-threading.

Combined, they make our computers, laptops, tablets, smartphones, and connected equipment more powerful and, ultimately, more valuable. However, there are plenty of upgrades you can make to your current PC to help modernize it and improve performance.