Understanding the differences between CPU, GPU, and APU
Is there a difference between a CPU, GPU, and APU?
Most of the hardware in your PC is associated with an acronym, and as technology advances and the number of parts increases, keeping all those names straight can be confusing. For the sake of keeping it all straight and to potentially help you get the hardware you need, let's take a look at the differences between the terms CPU, GPU, and APU.
What is a Central Processing Unit (CPU)?
The CPU can be considered the brain of your PC. It has a hand in pretty much all tasks and calculations carried out from all hardware, making it essential to your device's health and performance. Most modern PC CPUs employ multiple cores to handle multiple tasks at once, and overall performance is measured in gigahertz (GHz). For example, if a CPU has a base clock speed of 2.4GHz, it should be able to process up to 2.4 billion instructions in a second.
When it comes to CPU manufacturers, you'll likely hear about Intel and Advanced Micro Devices (AMD). Both create products that can run Windows, and, especially now that AMD has Ryzen, there's a shrinking gap between the two companies when it comes to price and performance.
Performance does vary quite widely across all CPUs from both manufacturers, offering up plenty of options when it comes to price and power consumption. You can find a low-performance CPU that's great for word processing, web browsing, and battery life, while you can also find a high-performance CPU that will absolutely shred anything you throw at it but will also suck up power like a vacuum in comparison.
We've written extensively about CPU technology and choosing the right CPU for your PC, so be sure to check out these links for more information.
- What is TDP and why should you care about it?
- How to balance price and performance in a new CPU
- Best CPU for your custom PC
- What you need to know about motherboard CPU sockets
- Everything you need to know to find the right CPU for a custom PC
- How to install an Intel CPU
- Why the new Ryzen chips will benefit AMD and Intel users
- Intel Core i3, i5, and i7: Which processor is best for you?
- Intel Y-Series vs. U-Series Ultrabook CPUs: What's the difference?
What is a Graphics Processing Unit (GPU)?
The GPU in your PC is essentially responsible for what you see displayed on the monitor(s) connected to your PC. There are typically two types of GPU: integrated and dedicated (also called discrete). Integrated GPUs share space with the CPU's chipset, while dedicated GPU's are a separate piece of hardware connected to a separate bus.
A GPU is designed to focus on big jobs that require a lot of power. Intensive gaming, VR, and video editing are all tasks associated with GPUs, thanks to the high number of cores available. While the CPU is the captain of your PC's team, the GPU can be considered the grunt, ready to accept the most strenuous jobs.
Like the CPU, we've written a lot about graphics cards, so be sure to check out these links for further information.
- Everything you need to know about the GPU
- Best graphics card
- Best graphics card for under $200
- How to upgrade your PC's graphics card
- How to install a new graphics card
- The ultimate GPU buyer's guide
What is an Accelerated Processing Unit (APU)?
APU is a term that AMD came up with to denote a GPU integrated into a CPU's architecture. Both the graphics processing cores and the standard processing cores share the same cache and die, and data is transferred through the same bus.
Why create an APU? Having both the CPU and GPU in the same spot allows them to work more efficiently for increased processing power. Likewise, having the GPU and CPU integrated is usually more energy efficient than having a CPU and a separate, dedicated GPU. Many modern APUs are powerful enough for non-intensive gaming; however, an APU will almost always be trumped by a modern dedicated GPU.
The first APU, using codename Llano, was announced by AMD back in 2011, but the project had been in the works since about 2006. If you're wondering where Intel stands in all this, most of their CPUs also employ integrated graphics. For example, the Intel Core-i7-8700K, commonly paired with a powerful dedicated GPU, does have Intel UHD Graphics 630 built right in. The term APU, however, isn't used by Intel, likely due to the heavy connection with AMD.
Windows Central Newsletter
Get the best of Windows Central in your inbox, every day!
Cale Hunt is formerly a Senior Editor at Windows Central. He focuses mainly on laptop reviews, news, and accessory coverage. He's been reviewing laptops and accessories full-time since 2016, with hundreds of reviews published for Windows Central. He is an avid PC gamer and multi-platform user, and spends most of his time either tinkering with or writing about tech.
Small note: the number of instructions per seconds in a CPU is not equal to the frequency, but it varies vastly among different processors, as well as the specific instructions being executed.
Also, other factors come into play (cache hits/miss for example) that can significantly reduce the number of instructions performed for clock cycle.
Bottom line, a CPU with a higher frequency isn't necessarily faster than one with a slower clock.