Technology Explained

How to Compare Different CPUs the Right Way

Mihir Patkar 02-08-2016

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


The bad news is that you can’t just rely on clock speed or cores, which are the two most heavily advertised aspects of processors. The good news is that you don’t need to know how a CPU works What Is A CPU and What Does It Do? Computing acronyms are confusing. What is a CPU anyway? And do I need a quad or dual-core processor? How about AMD, or Intel? We're here to help explain the difference! Read More , although that can prove useful.

The other good news is that there are sites out there that make such comparisons easier. In this article, we’ll tell you exactly what matters and what doesn’t when comparing different processors, and how to compare them the right way.

Clock Speed Isn’t Everything

Clock speed and cores are the most heavily advertised aspect of processors. Clock speed is usually noted in hertz (e.g. 3.14 GHz) while the number of cores is usually advertised as dual-core, quad-core, hexa-core, or octa-core What Do "Dual Core" and "Quad Core" Mean? These days, most CPUs are dual-core, quad-core, or octo-core. But what does that even mean? Here's everything explained. Read More .


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 the clock speed 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.

Compare clock speeds only when you are trying to decide between two CPUs from the same family and same number of cores. What this means is that if you’re looking at two quad-core Intel Core i5 Skylake processors Intel Skylake CPUs: 3 Things to Know Before Upgrading Thinking of upgrading to an Intel Skylake CPU but not sure if you should? Here's what you should know to help make that decision easier. Read More , 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 Intel Core i3 vs. i5 vs. i7: Which CPU Should You Buy? Confused by the differences between Intel Core i3, i5, and i7 processors? Here's what you need to know in layman's terms and which CPU to buy. Read More 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 actually 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.


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 benchmark tests PC Benchmark Tests: What Are They, And Do They Actually Matter? There are loads of technical sites on the Internet that deal in benchmarks - a whole host of charts and numbers for almost any piece of hardware on the market. But what do they mean? Read More .

Passmark’s full list of CPU benchmarks has a single-threaded rating for each CPU.


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 5 Little-Known Specs That Could Be Slowing Down Your PC We'll take a look at five lesser known factors that affect your computer's performance, and show you how you can always get maximum bang for your buck when upgrading. Read More ! So always check the cache specs of a processor before you purchase it.


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 it a second time, thus being faster.

Processors have different levels of cache, starting with L1 and going up to L3 or L4, and you should only compare cache size at the same level. If one CPU has L3 cache of 4 MB and another has L3 cache of 6 MB, the one with 6MB is the better choice (assuming clock speed, core, and single-threaded performance are all comparable).


Integrated Graphics Matter, Too

Intel and AMD have combined the CPU and the graphics card into an APU What Is the Difference Between an APU, CPU, and GPU? Confused about computer processor acronyms? It's time to learn the difference between an APU, CPU, and GPU. Read More . New processors can usually handle the graphics requirements of most everyday users without requiring a separate graphics card.


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.


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 The 10 Best Free Benchmark Programs for Windows Use these fantastic and free benchmark software for Windows to troubleshoot your system and keep it updated. Read More 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.


The easiest and best way is to head to CPUBoss. This site compares two processors and gives ratings Do You Really Need The Most Expensive CPU? Find Out With CPU Boss Picking out a CPU for your next computer is no mean feat. Of course, if you build your own desktop, you can usually go with a single motherboard and just swap out the CPU as... Read More  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 scored higher is the better one. CPUBoss also compares integrated graphics, telling you which APU has the better graphics performance.


In case you are looking for more details than what CPUBoss provides, I’d recommend the AnandTech CPU Benchmark Tool. Here you can browse in-depth benchmarks conducted by one of the best independent hardware review sites 5 Computer Hardware Review Sites For The PC Enthusiast Read More  and even compare two processors side-by-side.

Other Factors That Affect Performance

When it comes to overall performance, keep in mind that your processor is only as good as the rest of the hardware. If you buy a great processor and only stick in 2 GB of RAM, then it will be bottlenecked in speed.

Which processor have you bought, and why? What do you first look for in a CPU? Tell us your thought on purchasing processors today.

Related topics: AMD Processor, Buying Tips, Computer Parts, Computer Processor, CPU, Intel.

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  1. Joester
    August 18, 2016 at 4:07 pm

    Other Factors That Affect Performance
    When it comes to overall performance, keep in mind that your processor is only as good as the rest of the hardware. If you buy a great processor and only stick in 2 GB of RAM, then it will be bottlenecked in speed.

    Who else laughed at this? They're talking about Intel i-Series and AMD A-series.. and now they talk about 2GB of Memory.. uh, what? Good luck finding Memory with DDR4 with 2GB of Memory.

  2. Pranav
    August 3, 2016 at 4:58 pm

    Good article.

  3. Anonymous
    August 3, 2016 at 10:06 am

    Intel , always......