If defining your purpose is the conceptual first step in building a PC, then picking the central processing unit (CPU) is the first concrete choice you make toward achieving your purpose. The CPU determines your PC’s relative computing weakness or strength, what data tasks it can handle and how efficiently.

Computer Processors

Generally, the more ambitious your PC purpose, the more advanced a CPU it will require. So in order to outfit your PC with a CPU that will enable it to do what you need it to, it’s necessary to really understand what you’re asking of your PC. Do you want to use it primarily to surf the internet and type documents for work? Do you need advanced video and image editing capabilities? Or are you looking to build the best possible gaming PC for your buck? These different workloads all require different levels of CPU power.

Basically, there are two different categories of PC workload: Single-threaded and multi-threaded.

Average PC users largely engage in single thread workloads like internet browsing, word processing, and audio streaming. To a lesser extent, they probably do some multi-threaded work such as editing photographsencoding video content, and some level of gaming.

The rule of thumb is that single-threaded workloads are best accomplished with CPUs that have a high clock speed per core; having a large number of cores to utilize is less important. Conversely, multi-threaded workloads usually run more efficiently with multi-core CPUs.

Intel Ryzen

PC builders who want to enable heavy multi-threaded workloads would do well to look into Intel’s hyper-threading technology. It allows multiple functions to take place simultaneously on a single core. This results in greatly accelerated performance of multi-threaded workloads. (Caveat: You must make sure that your operating system supports SMT (simultaneous multi-threading) and offers special optimization in order to properly utilize hyper-threading.)

And then there’s the “no more than four” rule. Experienced PC builders may get the idea in their heads that more cores is automatically better, but this isn’t always so. Almost invariably, consumer software -- and this includes games -- are not designed for CPUs with sky’s-the-limit cores. This is why Intel’s previous mainstream CPUs max out at four cores, now we can see mainstream CPU upping their core count up to 8, making it a more capable processor for heavy rendering workloads.

CPU Coolers

 

You’ve probably heard the term “overclocking” and may believe that it is a one-way ticket to all around better CPU and hence PC performance. While it’s indisputable that a higher clock speed supplies an extra power shot to your CPU, that extra power comes with a price. First of all, it increases power consumption, heat, and noise -- three drawbacks that may not be worth the boost, figuratively or literally. For instance, a CPU running at factory speed may be fine with an average cooling system, but overclocked, it may suddenly require another fan (more noise) or even a liquid cooling radiator.

Another tip is to make sure your CPU is compatible with your motherboard. Whichever you purchase first, it is a good idea to research them simultaneously to make sure your CPU doesn’t leave you stuck with a motherboard you don’t care for or vice versa.

CPU Installation

Finally, you will notice that many CPUs come with some built-in graphics processing, which is fine for builds with minimal graphics requirements. However, if you are building for gaming or entertainment, expect that you will need to complement this with a purpose-built GPU.