The Central Processing Unit (CPU), also known as a processor, is the brain of the computer and is thus its most important component. Unfortunately, comparing two different processors side-by-side can be tough, which can complicate any purchases you might make.

Thankfully, there are many sites out there that make CPU comparisons easier. In this article, we'll tell you exactly what matters the most and what doesn't when comparing different processors and how to compare processors the right way.

Clock Speed Isn't Everything

Clock speed and cores are the most heavily advertised aspects of processors. Clock speed is usually noted in hertz (e.g., 3.14GHz), while the number of cores is usually advertised as dual-core, quad-core, hexa-core, or octa-core.

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Are you curious about what makes a CPU better than another and how to compare CPUs accurately?

For a long time, it was this simple: the higher the clock speed, the faster the processor, and more cores meant better speeds. But processor technology today isn't dependent as much on clock speeds and cores because CPUs now have several other parts that determine how fast they can perform.

In a nutshell, it comes down to how much computing can be done when all parts of a CPU come together in a single clock cycle. If performing Task X takes two clock cycles on CPU A and one clock cycle on CPU B, then CPU B might be the better processor even if CPU A has a higher clock speed.

Overall, you can't just rely on clock speed or cores, which are the two most heavily advertised aspects of processors.

You should compare clock speeds only when you are trying to decide between two CPUs from the same family and the same number of cores. What this means is that if you're looking at two quad-core Intel Core i5 Skylake processors, then the one with the higher clock speed will be faster.

For any other scenario, the clock speed or cores don't always indicate performance. If you're comparing Intel Core i3 vs. Core i5 vs. Core i7 processors or Intel Core i5 vs. Core i7 vs. Core i9 processors, then clock speed and number of cores don't matter. And if you're comparing Intel vs. AMD or an AMD A10 vs. AMD A8 vs. AMD FX, then clock speed alone won't tell you much.

Check Single-Threaded Performance

The dirty little secret in the computer world is that even though you're buying a processor with four cores, all four of those cores might not be used when you're running applications.

Most software today is still single-threaded, which means the program is running as one process, and a process can only run on one core. So even if you have four cores, you won't be getting the full performance of all four cores for that application.

PassMark's CPU Benchmarks List

That's why you also need to check the single-threaded (or single-core) performance of any processor before buying it. Not all companies explicitly release that information, so you'll need to rely on third-party data from reliable resources like Passmark.

The good thing is that you can use Passmark's CPU benchmarks list to compare different kinds of CPUs with just one click.

Moreover, if you're not a geek and want to explore more, we've already covered a detailed guide on what PC benchmarking is and methods to benchmark your PC using different processor comparison tools.

Cache Performance Is King

The cache is one of the most under-appreciated parts of a CPU. In fact, a cache with poor specs could be slowing down your PC. So, you should always check the cache specs of a processor before you purchase it.

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Cache is essentially RAM for your processor, which means that the processor uses the cache to store all of the functions it has recently performed. Whenever those functions are requested again, the processor can draw the data from the cache instead of performing them a second time, thus making it faster.

Integrated Graphics Matter, Too

Intel and AMD have combined the CPU and the graphics card into an APU. If you've ever purchased or built a gaming-oriented PC, you may know the difference between an APU, CPU, and GPU.

Because of recent technological changes, new processors can now usually handle the graphics needs of most people without requiring a separate graphics card.

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These graphics chipsets also vary in performance depending on the processor. Again, you can't compare an AMD to an Intel here, and even comparing within the same family can be confusing. For example, Intel has Intel HD, Intel Iris, and Intel Iris Pro graphics, but not every Iris is better than HD.

Meanwhile, AMD's Athlon and FX series come without graphics chips but cost more than the APU-centric A-Series, so you'll have to buy a graphics card if you're getting an Athlon or FX processor.

3dMark Processor Comparison List

In short, graphics processing on CPUs is still quite confusing, but you still need to pay attention to it! The best option is to consult third-party benchmarks and look for recommendations.

Futuremark developed the 3DMark graphics test, which is one of the best free Windows benchmark tools out there. You can check the 3DMark Physics Score of any processor and compare it to others in Futuremark's processor list, which should give you a fair idea of which CPU has better graphics.

The Best Way to Compare CPUs

All of these factors come together to make CPU comparisons a difficult proposition. How do you know which one you should buy? Here are a few tips that may help.

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The easiest and best way is to head to CPUBoss. CPUBoss is one of the best sites for an effective CPU comparison in minutes. This site compares two processors and gives ratings and explains the differences between the two in terms that any non-techie can also understand.

CPUBoss doesn't perform its own benchmarks but instead collates them from different sources like PassMark, PCMark, CompuBench, GeekBench, SkyDiver, and more. It basically saves you the trip of going to many sites.

The CPUBoss score is a safe parameter in making your purchase decision, with the simple idea that whichever processor scores higher is the better one. CPUBoss also compares integrated graphics, telling you which APU has the better graphics performance.

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In case you are looking for more details than what CPUBoss provides, we'd recommend the AnandTech CPU Benchmark Tool. Here you can browse in-depth benchmarks conducted by one of the best independent hardware review sites and even compare two processors side-by-side.

Other Factors That Affect Performance

When it comes to overall performance, it's important to remember that your processor is only as good as the rest of your hardware. If you buy a high-end processor but only put in 2GB of RAM, the processor's performance will be slowed down.

Apart from the processor and RAM, additional factors affecting your PC's performance include the number of apps operating in the background, throttling issues, clock speed, and so on.