The GPU handles rendering and computing tasks, the CPU is the brains of the computer that tells the other components what to do, and an APU is AMD’s take on a CPU/GPU hybrid that can do both of the aforementioned tasks while being power-efficient and cost-efficient, albeit not as powerful overall.
PC lingo can feel like a foreign language in itself. Navigating all the confusing terms, acronyms, and jargon can be very confusing, especially if you’re new to the whole PC building thing.
Among these acronyms are three that you’re certain to encounter when building a PC: CPU, GPU, and APU. Today, we’ll take a closer look at what these acronyms mean and shed some light on the differences between them.
What Is A GPU?
A GPU, or graphics processing unit, is pretty self-explanatory: it is responsible for rendering, be it simple things like the operating system’s GUI, image files, and video files, or something more complex such as video games and professional software used for animation, video editing, 3D modeling, etc.
Produced as a programmable electronic circuit card, the GPU can perform high volume, repetitive computations very rapidly to process images or frames that are then fed to a monitor. A modern GPU consists of hundreds of cores (CUDA cores for Nvidia and Stream processors for AMD), which compute large clusters of data in parallel to one another alongside a certain amount of integrated VRAM memory.
GPUs come in different sizes and are cooled by different types of cooling solutions but they all interface via a PCI Express (PCIe) slot on the motherboard.
However, GPUs can also be housed inside external GPU enclosures, in which case they interface with a PC or laptop via a Thunderbolt 3 port. This makes them a great choice for laptop users in particular, as they can easily give a laptop a big performance boost. GPUs work hard and generate a lot of heat, so they don’t fare as well inside a cramped laptop chassis. On the downside, Thunderbolt 3 is not as fast as a PCIe x16 connection is, so external GPUs don’t perform as well as internal ones.
On top of that, integrated GPUs exist, too. And as the name suggests, they are integrated with either a CPU or a motherboard, but the former is more common today. These GPUs don’t have their own dedicated VRAM, so they utilize a portion of the available system RAM. That said, they are cheaper to produce but also far less powerful than regular graphics cards, thus being best-suited for casual users who don’t intend on using their PCs for gaming or as workstations.
Nvidia and AMD have been the leading forces in the dedicated GPU market for a while now, the former more so than the latter. Namely, Nvidia dominated the high-end and the upper mid-range of the price spectrum while AMD generally offered users better value for their money when it came to the low-end and mid-range solutions, but their GPUs still weren’t as popular as Nvidia’s in the recent years.
As for integrated graphics, Intel HD Graphics, Iris Graphics, and Iris Pro Graphics are what you’d usually find in devices that use an Intel CPU, while AMD has a selection of APUs that also fill the same role, but more on that later.
What Is A CPU?
The CPU, or central processing unit (colloquially also commonly referred to as a processor), is a computer by definition – to put it bluntly, it is an extremely powerful calculator able to handle countless computations and calculations at any given moment and it is the brains of every computer, processing information and telling all the other components what to do.
A modern CPU houses billions of transistors and is comprised of multiple cores, which allow it to handle multiple tasks at once, whereas a single-core CPU could handle only one task at a time, merely giving off an illusion of multitasking by switching between different tasks quickly.
And while CPUs with four cores were serious stuff only 10 years ago, we now have mainstream CPUs that can have as many as sixteen cores, which can then further be divided into virtual/logical cores via hyper-threading/multi-threading.
In regard to speed, it is measured in gigahertz (GHz), and a single hertz equates to one instruction, so a 3 GHz CPU can handle a whopping 3 billion instructions each second. Needless to say, a faster CPU equates to a faster and more powerful PC, provided that the software can make proper use of the hardware’s capabilities.
And though each CPU comes with a default factory clock, many CPUs can be overclocked, thus becoming capable of processing even more instructions each second. However, overclocking a CPU also means that it will generate more heat, so a third-party cooler is usually a must if you want to squeeze any serious extra performance out of a CPU.
However, a CPU isn’t as important for gaming as a GPU is, as it is the GPU that does most of the heavy lifting when it comes to rendering detailed 3D environments in real time. The only issue that a gamer needs to worry about in this regard is bottlenecking. Basically, if a CPU can’t keep up with a GPU, then the GPU won’t be utilized to its fullest extent. Fortunately, a mid-range CPU is usually more than adequate, even for high-end gaming. And if you want to play it safe, this site can be a useful tool.
Today, most CPUs found in desktops and laptops are manufactured by Intel and AMD, and they have been on fairly even terms since AMD’s Ryzen leveled the playing field in 2017. There are other companies that manufacture CPUs, too, though they mostly fit in specific niches. These include recognizable names such as IBM, Apple, Samsung, Qualcomm, HiSillicon, Acer, and others.
What Is An APU?
And finally, we have the APU, the accelerated processing unit. This moniker was invented by AMD and the first generation of APUs was released in 2011.
But what exactly are they?
Put simply, an APU is comprised of both CPU and GPU cores on a single die. While there is a technical difference between an APU and an integrated GPU, their application is pretty much identical: they serve as approachable entry-level graphics solutions for budget PCs and non-gaming laptops. Plus, both the PlayStation 4 and the Xbox One, including the beefed-up Pro and X variants that would come later on, utilized AMD’s Jaguar APUs.
At the moment, AMD has several series of APUs compatible with the current AM4 socket:
- The A-Series APUs, which are the weakest of the bunch and most commonly used in the more affordable PCs and laptops
- The new Athlon series APUs, which are newer, generally more powerful than the A-series, and come with Vega graphics cores
- The Ryzen APUs which are the most powerful APUs made so far
Ultimately, APUs are quite efficient and have low power consumption but the performance that they offer isn’t quite stellar– that is, excluding the new Vega-equipped APUs that really do push the boundaries regarding what kind of in-game performance one can expect from an APU.
As a matter of fact, the Ryzen 3 2200G and the Ryzen 5 2400G can actually rival some low-end graphics cards and they absolutely smoke Intel’s integrated graphics solutions in benchmarks, making them very appealing picks for gamers who are on a tight budget. Still, they are only budget solutions, and they can’t keep up even with the likes of the GTX 1050 or the RX 560.
The Bottom Line
So, to sum up:
- CPU – central processing unit, the brains of the operation that does the arithmetic and ensures the rest of the computer components do what they’re supposed to do.
- GPU – graphics processing unit, the heavy lifter who ensures that the in-game landscapes look as good as the CPU says they should look.
- APU – accelerated processing unit, a CPU/GPU hybrid, a jack of both trades but a master of neither. Power-efficient, cost-efficient, and can save space in laptops and notebooks, but is not powerful enough to run AAA games properly.
At the end of the day, if you’re trying to decide whether an APU would be a better choice for you instead of the classic CPU + GPU combo, then you only need consult your wallet. As mentioned above, they can be a great means of saving money when building a budget gaming PC, but even the most powerful APU currently available (the Ryzen 5 2400G) would have a hard time with anything that’s not an indie or an eSports game.