Assemble a Computer

What Is a Processor?

The central processing unit (CPU), or processor, is responsible for the general functioning of the computer; it runs the operating system and coordinates operations between the various parts that make up the complete system. Your PC's power is based on the CPU.

The two main manufacturers of PC CPUs are Intel and Advanced Micro Devices (AMD). Both companies have a range of models at different levels of cost and performance - for example:

• Intel processors are branded as Atom, Celeron, Core i3, Core i5, Core i7, Core i9, and Xeon.

• AMD’s current (2021) product line is the Ryzen family, with previous ones being Athlon and Opteron. 

How to Choose a Suitable Processor

When choosing a processor, the aim is to balance cost and performance.

CPUs are broadly categorized by:

• Manufacturer

• Socket type

• Clock speed

• Number of processor cores

• Generation

• Cost/performance

• Hyperthreading

• Processor features

• Motherboard-based GPU

Let’s look at each of these points in detail:

Manufacturer

Choosing a manufacturer generally comes down to a mixture of brand preference, cost/performance, and product availability.

Socket Type 

AMD processors will not plug into motherboards designed for Intel CPUs and vice versa. In addition, both manufacturers have released different CPU pin/socket types over the years as feature requirements changed.

Examples of CPU motherboard socket types:

Clock Speed 

Processors are rated by how fast they operate, determined by their clock speed in gigahertz (GHz).  

Processor Cores 

Modern CPUs contain multiple processing units (cores). Dual or quad cores are adequate for a general desktop PC. More cores may help with intensive applications (computer-aided design, image editing, virtualization, etc.), but remember that the GPU performs the image rendering for gaming and other special applications, so having many more may not make much difference.

Generation 

Both Intel and AMD release new CPUs regularly. Sometimes, older generation ones can be a good bargain, provided they meet other technical requirements, and you can still obtain motherboards with the proper socket type.  

Cost/performance 

Sometimes, a CPU with equivalent specifications from an alternative manufacturer might be cheaper. Product availability might factor in choosing your processor.

Hyper-Threading 

Some CPUs can load a core with two sets of work simultaneously. Intel calls this hyper-threading, and AMD calls it simultaneous multithreading (SMT). The net result could be a two-core CPU with SMT that looks (to the operating system and applications) as if it has four CPU cores. CPUs with this feature are often cheaper than ones with true cores, but performance is not the same. 

Processor Features 

Some CPUs include additional instructions for specific applications, such as image editing, AI, cryptography, and virtualization.

Virtualization is the act of running another copy of an operating system in a window on your PC; this is useful for software testing and program development.

Check your application software to see if it requires a particular processor feature. Things to look out for are:

Motherboard-Based GPU (Integrated Graphics)

If a motherboard-based GPU is sufficient, you must specify a processor that includes that functionality.

AMD and Intel state whether a particular CPU includes integrated graphics in the specifications. AMD also produces some processors with an enhanced graphics processor called an accelerated processing unit (APU).

Here is a summary of current processor models and their typical use:

The table above is very generalized, and it is difficult to match specific CPUs to particular, real-world workloads.

To help with decision-making, read the customer comments on the supplier’s website. Also, note how many comments there are; more entries imply a more popular CPU.

Checklist

Choosing a CPU can become complex if you decide to investigate all the technical parameters. These key points will be sufficient in most circumstances:

• What’s the intended use? Simple office apps don’t need a top-end processor.

• Do you require specific CPU features? For example, are you going to run a virtualization application that requires VT-x and VT-d (AMD AMD-V)?

• Is there a brand preference? This may be determined by price, availability, or required features.  

• Does the CPU need to have integrated graphics? 

• What’s your budget? A previous generation CPU may be a better deal.

Your Turn!

🎯  You need a CPU!

⚙️  Go see what’s out there and pick one suitable for your PC - which, you might remember, is intended for general, front-office use. Also, give an example of a CPU that’s less suitable. For both cases, note the reasons for your choices.

✅  Once you’ve finished, see how your selections compare with mine in the Example Solutions document: .docx / .odt.

Let’s Recap!

• The general computing power of your PC is based on your CPU.

• The two main processor brands are Intel and AMD.

• Each manufacturer offers multiple ranges of CPUs.

• Some CPUs have specific features (such as Intel VT-x) that some applications may need, so make sure the CPU you choose is suitable.

• Some CPUs have integrated GPUs that are sufficient for most non-graphics intensive tasks (i.e.,  a desktop PC for general office applications), meaning that a separate graphics card is unnecessary. 

We’ve now investigated CPUs and the key points for choosing one, but there’s one more thing about them that we need to cover to ensure that your PC works reliably: the processor cooling system.