Learn how to Select a CPU

There are few components in your system that are as important as the central processing unit (CPU). From generating game logic to running sophisticated applications to completing seemingly mundane computing tasks, your CPU does most of your computer's actual computing. So knowing how to choose a CPU is important when you are in the market for an upgrade.

However, buying the right CPU can be confusing. Cores, threads, clocks, and cache are all numbers that we can access right away, but understanding them takes a little bit of expertise. At the end of this guide to buying CPUs, we'll tell you how to choose a CPU, what to look for and why.

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AMD versus Intel

Intel Newsroom / Intel Corporation

There are two main CPU manufacturers when it comes to desktops and laptops: AMD and Intel. Until 2017, Intel was the only real choice unless you went on an ultra-budget, but today whether you go for an AMD or an Intel CPU, as long as you buy the right one for what you get If you want to do with your new system you will have a fantastic experience.

That's not to say that there aren't any instances where we would likely recommend one company's products over the others, but the difference isn't as important as it used to be and there are other factors that may be more important to you ( read) our special AMD versus Intel guide for more).

One important note, however, is that if you plan to build a computer you must purchase compatible components (here are some helpful tips). An Intel motherboard will not work with an AMD CPU and vice versa.

You can use an Intel solid state drive in an AMD motherboard or an AMD graphics card in an Intel PC. However, when it comes to CPUs and motherboards, you have to buy what is compatible.

CPU labels and generations

You can find out a lot about a processor simply by knowing the generation it is from and the level it is in in that generation. AMD and Intel have different naming schemes for their processors, and being able to decode them is important. Newer processors tend to be better. As we will explain in this guide, the ability to identify processors individually allows you to find out what is relevant and what is not.

The latest AMD processors are part of the Ryzen 5000 series. The first number notes the generation, while the second number indicates where the processor is in that generation. For example, the 5600X and 5800X are both from the Ryzen 5000 series, but the 5800X is a faster and more powerful processor within this generation.

Unfortunately, the numbers themselves don't mean much. For example, you can assume that the Ryzen 5000 processors are the fifth generation of Ryzen processors. However, this is not the case (it is actually the fourth generation of Ryzen processors and only the third architectural change). Similarly, the 5800X is labeled the Ryzen 7 Tag and the 5600X is labeled the Ryzen 5 Tag, while the 5900X has a more suitable Ryzen 9 Tag.

The numbers themselves are not important. This is how they compare. A Ryzen 5900X is of a newer generation than a 3900X, and a 5800X and 5600X are of the same generation, but the 5800X is faster.

Intel's naming scheme is similar: use the first number to record the generation and the second number to record the location within that generation. Like AMD, Intel also categorizes its processors in levels (e.g. Core i7 and Core i9). Knowing this, we can choose the Intel 10900K as the 10th generation processor in the i9 tier. Again, higher is better.

However, there is nothing simple about naming the CPU. Like AMD, Intel is also breaking away from its naming convention. For example, the 10400 and 10600K are both 10th generation i5 processors. However, higher is still better, so the 10400 generally performs worse than the 10600K.

Intel also adds a suffix to most processors that identifies certain features (or the lack of such features). There really is no reasonable explanation for the suffix letters and what they mean. So let's just list them instead:

  • G1-G7: Graphic layer
  • E: Embedded
  • Q: Requires discrete graphics
  • G: Contains discrete graphics
  • H: High performance optimized for mobile devices
  • HK: High performance optimized for mobile devices, unlocked
  • Head office: High performance optimized for mobile quad-core
  • K: Unlocked
  • S: Special edition
  • T: Optimized for performance
  • U: Mobile energy efficient
  • Y: Extremely energy-saving mobile

Fortunately, you won't come across most of the suffixes when purchasing a processor. The main ones to remember are the F and K for Intel desktop processors. HK and U are most common on mobile devices.

Cores and threads

Dan Baker / Digital Trends

If you want to know how to choose a CPU, you need to consider cores and threads. Cores are like individual processors that are all grouped together on the same chip. Traditionally, they can do one task at a time, which means that more cores improve a processor when multitasking. Modern software is far better at using more cores at the same time to do the same job, so more cores can make some software run faster too.

Threads are the number of tasks a CPU can do at the same time. Many modern processors have simultaneous multithreading (hyperthreading on Intel CPUs), with which processors can use the spare core power for additional tasks. For this reason, a CPU with four cores and eight threads or six cores and 12 threads is often listed. These extra threads aren't as fast as the cores themselves – because they are making effective use of parts of the CPU that are underutilized – but they usually improve performance noticeably.

Some software can consume more cores and threads than others, so the number of cores and threads your CPU has is a great indicator of potential performance. Having more cores than you need will not speed things up beyond the limits of the software, and this can result in your individual cores not being as fast as those in smaller numbered chips.

If all you want to do is answer emails, browse the web, and watch Netflix, a dual core will do, although you'll find your four-core experience faster, especially if you want to multitask your system. Inexpensive six-core CPUs are also worth considering – especially if they are multithreaded at the same time, as is the case with AMD's low-end hexacore designs.

If you're a gamer you'll want at least a quad core CPU, and preferably one with eight thread support. There are advantages to using a six-core CPU, and some games can run moderately faster with eight cores. In addition, you will see very falling returns. For example, the Ryzen 7 5800X with eight cores is just as powerful as the Ryzen 9 5950X with 16 cores in most games (and costs about half the price).

If you're a video or audio editor, transcode video, or work with large databases, the sky is almost the limit to the number of cores you can use. However, if you move past eight cores, you won't see such big jumps in performance. Still, AMD's 12- and 16-core Ryzen 5900X and 5950X CPUs are two of the best multithreaded CPUs in the world. This shows that Cores can really come in handy when you have a lot of work to do.

There are even CPUs with up to 64 cores, but they are extremely expensive and should only be considered by professionals.

Clocks and IPC

Dr. Lisa Su, CEO of AMD, explains the performance of the Ryzen 3700X.

Another important aspect of CPUs is the clock speed. This is the megahertz (MHz) and gigahertz (GHz) rating and indicates how many collections of tasks a processor can perform per second. It's a fair representation of the speed of individual cores, though it doesn't tell the full story. If two processors of the same generation have the same number of cores, but one has a higher clock speed, performance will be faster.

Because higher clock speeds mean individual cores run faster, chips with higher clock speeds but fewer cores can perform better in certain applications that cannot use higher core and thread counts. For this reason, a 10-core processor like the Intel i9-10900K is comparable to a 16-core processor like the AMD Ryzen 9 5950X in many benchmarks. The 5950X has more cores and the 10900K has faster cores. This can be helpful depending on the applications you are using.

CPUs also have different instructions per cycle (IPC). This is the number of tasks that can be performed in each clock cycle (every second as measured by the clock speed) and depends on the underlying architecture. When using the 5950X and 10900K again, the 5950X uses AMD's Zen 3 architecture, which has a higher IPC rating than the 10th generation Intel design. That is, if a 10th generation Intel core and a Zen 3 AMD core are running at the same speed, the Zen 3 AMD core will be faster. More commands can be executed per clock cycle at the same speed.

While this may seem a little confusing, it underscores the importance of checking individual checks for processors. Head-to-heads, where two CPUs compete against each other in comparable tests, are also a great way to see how they work in the real world.

If you want a good rule of thumb, CPUs with higher clock speeds and newer architectures are faster for almost anything, but for productivity tasks, a modern one with more cores is usually faster.

Integrated graphics

CPUs can also have integrated graphics chips on the same chip so that they can operate independently of dedicated graphics cards. Intel CPUs labeled F (like the 9900KF) do not have built-in graphics, but most of the others do have some form of them. They're usually not powerful, but an integrated entry-level graphics chip like the UHD 620 can process between 30 and 60 frames per second in older esports games like CS: GO. You should keep the settings low to avoid frame rates stuttering during intense actions or heavy smoke.

Intel's 11th generation graphics chips (included in 10th generation Ice Lake processors) are available in Iris Plus configurations and offer decent gaming performance. In the tests by Anandtech, a GPU with 64 execution units on board the Core i7-1065G7 in a Dell XPS 13 in DotA 2 managed over 43 fps with detailed settings for enthusiasts at 1080p. We found it more than capable of playing Fortnite at 720p and 1080p. This is a big improvement over what we've seen with Intel onboard GPUs in recent years.

However, an even greater improvement was achieved with Intel's 12th generation Iris Xe graphics, which were first used on 11th generation Tiger Lake chips. When testing the top-notch i7-1185G7, we got an average of 45 fps in Civilization VI and 51 fps at 1080p in Battlefield V with medium settings. However, Fortnite struggled to only manage 34 fps at 1080p with medium settings in our tests.

Intel's Iris Xe graphics are still the most compelling integrated graphics solution available today. It's still a long way from a dedicated GPU, but a huge step up from previous generations of integrated graphics.

AMD's processors typically don't have built-in graphics on the desktop, although there are some Accelerated Processing Units (APUs) that do. They are more comparable to Intel's 11th generation graphics and offer reasonable performance in entry-level and esports gaming settings.

All AMD mobile CPUs have built-in Vega graphics. In some configurations, they can be suitable for gaming. We found that the RX Vega 10 provided more than comfortable frame rates on a Ryzen 7 3700U equipped laptop in Diablo 3 and Half-Life 2. You need to check the ratings of individual CPUs to see how powerful they are. There are other factors that can affect game performance, but you know that higher numbers of graphics cores usually translates into higher graphics performance.

Power and thermals

A Digital Trends employee installs an all-in-one CPU water cooler. Bill Roberson / Digital Trends

Performance is the number one factor behind most CPU purchases. If you can't get what you want faster than before with your new chip, what's the point of an upgrade? If you are looking for a quiet PC, an efficient PC, or a particularly compact PC, power and heat requirements are also important considerations.

Unfortunately, neither AMD nor Intel give particularly clear data on the performance and heat requirements of their processors, but rather bundle the two into an evaluation of the Thermal Design Power (TDP). This is expressed in watts and gives you a rough idea of ​​how much power the CPU is taking from the power supply and how capable a cooler is to keep it at safe operating temperatures.

Low-power laptop CPUs operate on just a few watts and reach a maximum output of 45W in the most rugged gaming devices. On the other hand, desktop processors can stretch up to 125W under certain circumstances, although they are typically between 65W and 95W lie.

In certain situations, TDP can also be an indication of the status of the underlying silicon of a processor where, due to their ability to manage additional performance, more powerful CPUs are ordered in the leading TDP tiers. However, this depends on each individual case and there is really no guarantee of a higher quality chip. It's also just particularly suitable for overclocking.

You should examine individual processor tests to determine how much power and cooling they actually require. However, if you're in the market for higher TDP CPUs that draw close to 100W, bigger, more powerful coolers are a reasonable option if you want a quieter PC.

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