What is a CPU, and How Do You Find a Good One?


We recently posted a new video on our YouTube channel about CPUs and how to find a good one. It’s the first video in a series explaining the various components of a PC. The goal is to give people a slightly deeper understanding of each component, and give some practical advice on how to pick out the right components for you.

Here’s the video:

And here’s all the info we cover in the video, in case you like reading better than watching:

CPUs are sort of like the brains of your computer. Everything you do on your computer goes through the CPU, which makes it an essential part of every PC.

There are two big manufacturers of desktop CPUs today: Intel, and AMD. Both manufacturers build CPUs that do the same thing: Do math in ones and zeroes at incredibly fast speeds to make computery things happen. (In other words, they perform all the logical operations that allow the computer to perform.) So, processing ones and zeroes is the goal of every CPU, whether it’s from AMD or Intel, but how each CPU accomplishes those computery goals is a little different.

First, let’s look at some specs on a popular Intel CPU, the i5 4690K.

The 4690K is a 4-core processor with a clock speed of 3.5 gigahertz. It currently retails for about $240, and it’s a CPU we recommend in some of our upper-mid-range PC builds.

Let’s compare those numbers to a popular CPU from AMD, the FX 6350.

The 6350 has 6 cores clocked at 3.9 gigahertz. But even though it has bigger numbers compared to the Intel CPU, this processor retails for about half the price at $120, and we recommend it in some of our lower mid-range computer builds.

So, what’s the deal here? Judging by the numbers, you might assume that the AMD CPU would be better than the Intel CPU. After all, it has more cores and a higher clock speed. Bigger numbers are better, right?

Unfortunately, it’s more complicated than that.

Despite having fewer cores that run at a lower frequency, this Intel CPU uses a more advanced, more complex architecture that allows it to be more efficient and perform better than this AMD CPU in most situations.

So, what do the numbers mean, if they don’t tell us how good the CPU is going to be? This is where things get tricky.

Our Intel CPU has 4 cores. You can think of cores kind of like “workers,” where one core equals one worker. One worker can get done one unit of work. So, you might assume that two workers should be able to get done two units of work, but in reality, it never quite works out with perfect scaling. Two workers can do somewhere between one and two units of work, depending on the process they’re working on.

So, with a process that’s easily broken up into multiple tasks, like video editing, you can take advantage of a lot of cores. Some other processes, however, might not be optimized to use all those cores efficiently.

To make things even more complicated, remember how we said our AMD CPU had 6 cores? Well, it actually kind of has 3 cores or 6 cores, depending on what it’s doing. It’s more like it has 3 workers who can often do the work of 6 workers, but we don’t want to complicate things further. Basically, think of cores as workers.

Clock speed determines how fast the workers can get tasks done. In other words, it’s the speed of each core. A higher clock speed means tasks get done faster, as long as we’re talking about raising or lowering the clock speed on the same CPU.

For example, if our AMD CPU that’s running at 3.9 gigahertz was instead running at 5 gigahertz, we know it would do that work faster.

However, clock speed comparisons don’t really work between two different CPUs. You can’t take two different CPU models and predict that one will perform better than the other simply based on the higher clock speed.

Like we mentioned a minute ago, our Intel CPU uses a more advanced architecture, so even though it only runs at 3.5 gigahertz, it’s more efficient and gets more done at a lower clock speed compared to our FX 6350. And to make things even more complicated, both of these CPUs can dynamically vary their clock speeds to either run faster or save power.

So, how do you actually figure out which CPU to buy, if those numbers don’t inherently tell you which one is better?

In short, the best way to figure out what CPU to buy is to compare real-world performance benchmarks or get recommendations from knowledgeable sources.

One great benchmark resource for comparing CPUs is Anandtech Bench. Under ‘CPU Product Benchmarks,’ we can choose to compare our FX 6350 and our i5 4690K. The benchmark tool will give us a series of direct measurements comparing how well the CPUs perform in real-world applications. Based on each individual metric, the benchmark should tell you if higher numbers or lower numbers are better.

For example, here’s an x264 HD video benchmark, showing us how fast our two CPUs encode x264 video. The FX 6350 is in blue and the i5 4690K is in orange:


As we can see from the first pass, the 4690K is about 50 percent faster at encoding x264 video. Since these are real-world, directly comparable numbers, you know what you’ll be getting for your money if you edit videos and decide to go with the 4690K over the FX 6350.

For another comparison, here’s a benchmark of each CPU playing Battlefield 4 with a GTX 770 graphics card:


As you can see, the 6350 and 4690K have nearly the same performance in Battlefield 4. So, if you’re building a PC that will mostly be used to play Battlefield 4 and similar games, it might make sense to save some money and go with the FX 6350.

Of course, people like us do this all day, so if you don’t want to get into this level of research, you can refer to a reliable resource.

Here are some basic ground rules for choosing the right CPU for you:

Cheap CPUs: If you just want to use your computer for browsing the web, word processing, playing old PC games, or watching YouTube and Netflix, you’d be fine with a low-end CPU in the $25 to $100 range.

Mid-range CPUs: Moderately priced CPUs ranging anywhere from $100 to $250 are usually good for more intense tasks such as playing the newest PC games, streaming games on Twitch or YouTube, or editing videos with professional software. These mid-range CPUs tend to be the best value for your money, and most of the CPUs we recommend would be considered mid-range.

High-end CPUs: You should probably only consider a really high-end CPU above the $250 range if you plan to do something really intensive, like 4K game recording, 4K video editing, really serious design or production work, or some other task that you know requires a high-end CPU.

TL;DR: If you buy a much more powerful CPU than you actually need, you might get a little extra performance, but you’ll experience greatly diminishing returns on your investment.

So, since the CPU is central to the performance of your computer, you definitely want to get one that’s going to be powerful enough for what you want to do, but think about how you want to use your computer and do your research to make sure you’re not spending more money than necessary.

Hopefully you now know a little bit more about CPUs and how to pick the right one for you. If you have any questions, feel free to get in touch with us over at logicalincrements.com, where we provide professional recommendations on the best PC hardware for the money.

Helpful links:

CPUs featured in this video:

Other links:

Image source: intel.com