Technology Explained

What Is the Difference Between an APU, CPU, and GPU?

James Frew Updated 24-04-2020

When it’s time to buy your new computer, knowing the difference between the CPU, GPU, and APU is a considerable advantage. It could even end up saving you money. This is especially true if you plan to build your own PC.

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The three technologies are often grouped but perform separate roles. Knowing the function of each, and whether you might need it, is crucial.
So, what exactly is the difference between an APU, CPU, and GPU?

Central Processing Unit (CPU)

This PC part is the CPU

The Central Processing Unit, or CPU, is the main brain of the computer. In early computers, the CPU was spread across multiple chips. However, to improve efficiency and reduce manufacturing costs, the CPU is now contained on a single chip. These smaller CPUs are also referred to as microprocessors.

Reducing the footprint of the CPU has also enabled us to design and produce smaller, more compact devices. Desktop computers can be found as all-in-one devices, laptops continue to get thinner yet more capable, and some smartphones are now more powerful than their traditional counterparts.

The CPU performs the core computing processes for your computer. Instructions stored in your device’s RAM are sent to the CPU for execution. This is a three-part system consisting of Fetch, Decode, and Execute stages. Broadly, this means receiving inputs, understanding what they are, and creating the desired output.

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Using this, your CPU aids everything from loading your operating system, opening programs, and even performing spreadsheet calculations. Resource-heavy operations like video games place the most significant load on your CPU. This is why benchmarking tests are usually performed against gaming standards.

CPUs are available in many variants ranging from energy-efficient single-core chips to top performance octo-cores. Intel uses its Hyper-Threading technology to make a quad-core CPU act as though it is an octa-core. This helps to squeeze the most power and efficiency from your CPU.

If this has piqued your interest in learning more, check out our guide to the CPU and its functions 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 .

Graphics Processing Unit (GPU)

A PC graphics card (aka video card or GPU)

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For all the advances made with CPUs, they still have shortcomings; namely, graphics. CPUs take input and work through it in linear steps. However, graphics processing requires multiple data to be processed simultaneously. The Graphics Processing Unit (GPU), reduces the strain on the CPU and improves your video performance.

Most computers and laptops are equipped with a CPU and GPU, but this isn’t always the case. Sometimes, especially at lower price ranges, your computer will come with integrated graphics instead of a dedicated GPU. If you aren’t sure which setup you have, take a look at our comparison between integrated and dedicated graphics cards Integrated vs. Dedicated Graphics Card: 7 Things You Need to Know Wondering if you should use an integrated vs. dedicated graphics card? Here's what you need to know to make your decision. Read More .

Both the GPU and CPU perform similar functions, but it is how they do it that differs. The GPU’s parallel structure is specially adapted for its purpose. This helps the unit achieve the billions of calculations per second required for gaming and video playback. The GPU is often situated on a separate graphics card, which also has its own RAM.

This enables the card to store the data it generates. It’s also thanks to this built-in RAM that the GPU can generate a buffer, storing completed images until you need to display them. This is particularly useful when watching videos, for example.

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As these cards are easily replaced, it’s often seen as one of the best upgrades you can make to your computer. High-performance graphics cards usually have a price tag to match. However, there are graphics cards for cheap gaming The 6 Best Budget Graphics Cards for Cheap Gaming Budget graphics cards are very capable these days. Here are the best budget graphics cards that will let you game on the cheap. Read More as well, giving an option at every budget.

Accelerated Processing Unit (APU)

Illustration of a computer processor
bodkins18/Pixabay

To reduce physical size and manufacturing costs, manufacturers have found ways to combine electronics components onto single chips. The latest iteration of this technology is System-on-a-Chip (SoC) devices. In this design, all the main electronics are combined onto a single die. This enabled the growth of low-cost computing devices and smartphones.

However, the precursor to SoC was the Accelerated Processing Unit or APU. These units combined the CPU and GPU onto a single chip to form a combined processing unit. Not only does this reduce cost, but it improves efficiency, too. Minimizing the physical distance between the two enables faster data transfer and increased performance.

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As GPUs are optimized for faster calculation speeds, the CPU can offload some work to the GPU. In a separate setup, the efficiency gains from this load sharing would be undermined by the physical distance and data transfer speeds between the two. However, the combined APU does make these gains possible.

Despite this, an APU doesn’t give the same performance as a dedicated CPU and GPU. Instead, they are best viewed as a step up from integrated graphics. This makes APUs an affordable upgrade for those looking to update their PCs.

Processor manufacturer AMD developed the APU. However, they weren’t the only ones to combine processors in this way. Intel also began to integrate the CPU and GPU, too. The main difference was that AMD released a dedicated line of APUs, whereas Intel and other companies merged them into their product lines.

For a more detailed breakdown, take a look at our guide to the APU and what it does What Is an APU? The Accelerated Processing Unit, Explained Checking out computer parts for an upgrade? You might have seen an "APU". What is it and how does an APU differ from a CPU? Read More .

APU vs. CPU vs. GPU: Now You Know!

Now we’ve covered the main processing units, you know there’s a lot of choices out there for your computer. If you opt for a separate CPU and GPU, you’ll likely spend more, but get more significant performance gains, too.

Selecting an APU is a compromise between budget and performance. If you’re currently running with integrated graphics, then an APU is a worthwhile upgrade that won’t break the bank.

However, before investing in an APU, CPU, or GPU, you’ll want to be sure you’re choosing the best value upgrade for your machine. In which case, you should consider which of these upgrades will improve your PC the most Which Upgrades Will Improve Your PC Performance the Most? Need a faster computer but aren't sure what you should upgrade on your PC? Follow our PC upgrade checklist to find out. Read More .

Related topics: AMD Processor, APU, Building PCs, Computer Parts, Computer Processor, CPU, Graphics Card, Intel, Video Card.

Affiliate Disclosure: By buying the products we recommend, you help keep the site alive. Read more.

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  1. Tom OConnor
    September 19, 2017 at 5:41 pm

    Although I've yet to use an APU, to me it sounds like the best choice as I can see how it would generate less heat. I've been using PC's not for about 20 years and have learned the hard way just how bad it is to run iot at excessive heat. In fact, lately I've completely gotten away from Desktops and run completely on Laptops/Notebooks while at home...an iPad while on the road, and I've gone so far as to remove my battery (tip to newer users) and run an external cooler and keep the temperature at 32-34 deg. celsius.

    • Brandon Clark
      November 12, 2017 at 2:09 pm

      If you have used an intel CPU in the last eight years then you have likely used an 'APU'. APU is a marketing gimmick that AMD uses, and it just means CPU with onboard graphics, something that intel has done since Sandy Bridge.

  2. Sidney Weisberg
    January 8, 2016 at 7:09 am

    Great Article I loved it helped me better understand so I don't look silly asking on the internet.

  3. Sahil
    November 15, 2015 at 7:13 am

    Thanks , GOOD Article

  4. Anonymous
    September 4, 2015 at 11:32 pm

    Thank You Very Much It Helped Me A Lot Thank You Very Much

  5. Anonymous
    August 21, 2015 at 6:18 am

    this makes it sound like hyperthreading is a good thing, its not. if an app only uses 1 thread then a cpu with hyperthreading will only process that thread at half speed

    • dinkles
      January 29, 2017 at 5:07 pm

      ummmm... dude, hyperthreading is a good thing... why on earth would it be a selling point for CPU's if it wasnt, theres a reason why i7's are better suited for some tasks over an i5...

    • SOC
      February 8, 2018 at 6:44 pm

      That is just not true, Hyper-Threading is essentially just an extra thread in each core that will only work when there is downtime on one of the cores (In case it's waiting for another core to finish before continuing).
      It increases performance by maximizing efficiency. It does NOT slow down single threaded tasks, it's just useless to have Hyper-Threading for single threaded tasks.
      Please don't spread wrong information.

  6. John
    February 27, 2015 at 6:18 pm

    Hi I only download say movies plus browse the net just want some speed computer with no problems don't play games., No number crunching or anything was looking at the amd6800 what you think

    Thanks
    Jock

  7. Tom
    February 3, 2015 at 5:37 am

    Hey there, thanks for that. Spelled out perfectly. So i'm wanting to get into Cinema 4D animation and want to build a rendering machine that is external to my iMac, connecting it via a Gigabit connection for network rendering so i can send jobs to it while continuing to work on my iMac without the massive lag effect rendering has on the computer.

    What would be the best setup CPU, GPU/Graphics card, RAM wise? Should i be looking to combine 8-12 GPU's? If so, do i need more than one CPU or motherboard? Do i need a lot of RAM (32+ GB) or is this covered off in the GPU?

    Now comes the tricky part... it needs to run OSX otherwise the iMac wont register it. So are there GPU's / CPU's / motherboards / RAM bla bla that won't be compatible with OSX?

    Its a bit question i know... but one i've wanted answered for some time!

    Cheers

  8. Norma
    July 25, 2013 at 2:43 pm

    Thanks for this article is really nice

  9. Mohammad Shajapurwala
    February 19, 2013 at 6:23 am

    thanks for coming up with such a great knowledge......its is very help full peace of details...thanks once again

  10. Humza Aamir
    February 15, 2013 at 1:24 pm

    Very informative, is there a way to find how many cores my GPU has? For bragging rights ;)

    • Mohammad Shajapurwala
      February 19, 2013 at 6:28 am

      hello hamza...!
      within GPU process is not divided.....it has full complete process.....u must be thinking of like quad core processor or like that stuff....but it is graphical unit section so deals completly....not a single process is hadle individually

    • Danny Stieben
      February 28, 2013 at 8:35 pm

      You can find it out by using tools such as CPU-Z or by simply researching the GPU online if you know the model number. Most retailers have such details on their pages.

  11. Scott Macmillan
    February 15, 2013 at 11:49 am

    Great article.It explained a lot to me about about what is happening under the hood.

    • Danny Stieben
      February 28, 2013 at 8:34 pm

      I'm glad I could help you better understand! :)

  12. Nevzat Akkaya
    February 15, 2013 at 7:22 am

    An article that definitely needs to get bookmarked. Thanks MUO and Danny.

    • Danny Stieben
      February 28, 2013 at 8:33 pm

      No problem! I'm glad you enjoyed it!

  13. Alberto Lerma
    February 15, 2013 at 4:59 am

    Why don't you drink a cup of bleach instead?? I've heard that if you do, in your next job you'll get paid 85 an hour without doing anything at all. Try it m8!! now go back to LH and stay there. Cheers.

    • DarknessTSG
      February 2, 2015 at 6:16 pm

      But I wanna hit WW with everyone else!!

  14. Mara Averick
    February 14, 2013 at 6:54 pm

    Timely article for me as I've been planning a low(ish) cost Linux build for an alternative development environment/fun project (although I'll never abandon my MacBook Pro). I was interested to read that GPUs pack the big punch in number crunching- since most of my 'heavy' work is with non-graphical data (I spend a lot of time in R, and, of course, in Terminal) I had been thinking I would skimp on the GPU, but it sounds like that would be a terrible idea... Right?

    • Anonymous
      February 14, 2013 at 10:30 pm

      Normally, you would use a GPU to do more of the number crunching involving physics and vectors, ie. more algebraic functionality rather than running process strings and terminal based applications really. GPU's are particularly useful in builds that focus on graphic design, CAD (Computer Aided Design) work, gaming (shadows, physics, simulated enviroments), or multi-desktop (more than 1-2 monitors).

      If you aren't going to be doing any of those, you can probably skimp on the GPU a little. :)

      • Mara Averick
        February 15, 2013 at 2:17 am

        Thanks, great advice! Sine my Adobe suite is all Mac I think my graphic work won't really play into this build- though I'm gonna look into some of the visualization packages I'll be using in R/R64, but I'm pretty sure the type of SVG-based map work I work with aren't all that complex graphically (despite being computationally mind-boggling at times)!

        • Danny Stieben
          February 28, 2013 at 8:31 pm

          I wouldn't totally ignore the GPU aspect of your build, but if I'd think that a mid-range GPU or APU should work out fine for you.