Computer graphics are an essential part of any modern computer system, even lightweight laptops. “GPU” stands for Graphics Processing Unit, and it is the part of the PC that is responsible for the on-screen graphics that you see.
What the GPU does
If you only use your computer for the basics ̵
For gamers or anyone who does work that can be GPU accelerated, such as 3D rendering, video coding, and so on, the GPU does a lot more work. Those people need to get a lot more out of their GPU, so let’s look further.
The different types of GPUs
There are two primary types of GPUs you can get for a modern PC: integrated and discrete. The latter has nothing to do with avoiding attention. Discreet in this sense means that it is separate or different.
Graphics cards are typically large, bulky drop-in components for desktop PCs with one, two or sometimes three fans. These cards contain the actual graphics processor chip and RAM for higher graphics loads such as video games. Fans keep the components cool.
Graphics cards for desktop computers are some of the easiest components to upgrade. You just drop the card into a PCIe x16 slot, connect a cable to the power supply (if necessary) and then install the drivers.
Laptops can also have separate GPUs. Rather than a bulky card, a discrete laptop GPU is just a chip soldered to the motherboard. Unlike those on a desktop, these are not that easy to upgrade.
Then there are integrated graphics, which are built directly into the processor. Not all CPUs have this. For instance, AMD’s desktop Ryzen CPUs are known for not having an integrated graphics card at all.
Intel’s desktop Core chips with model numbers ending with an “F” also don’t have a graphics card, as do the Core X series CPUs with model numbers ending with an “X”. Since these processors don’t have a GPU, they are sold at a lower price.
A processor without a graphics card is only a concern for desktops. Again, laptops are sold as a package deal, so they require a discrete GPU or an integrated graphics card built into the processor.
Modern processors with integrated graphics can be surprisingly powerful. Some are able to output selected older AAA titles with playable frame rates when graphics settings are lowered.
They are a cost-effective choice for those who can’t afford the graphics card of their dreams just yet. However, anyone who wants to play seriously needs a separate GPU.
What a GPU does
The easiest way to understand what a GPU does is to talk about video games. In a game, we can see a computer generated image of a person, a landscape or an intricately detailed model of a 3D object. Whatever we see, it’s all thanks to the graphics processing unit.
Video games are complex ventures that require many mathematical calculations to be performed in parallel to display images on the screen. A GPU is purpose-built to process graphical information, including the geometry, color, shadow, and textures of an image. The RAM is also specialized to hold a large amount of information that comes into the GPU and video data, known as the frame buffer, that goes to your screen.
The GPU will get all the instructions for drawing images on the CPU’s screen and then run them. This process of instructions to the finished image is called the rendering or graphics pipeline.
The basic unit to start creating 3D graphics is the polygon. More specifically triangles. Almost everything you see in a typical video game starts out as a huge collection of triangles. Other shapes can be used as well, but the vast majority are triangles.
These basic shapes, along with other lines and points, are known as ‘primitives’. They are built to create recognizable objects, such as a table, tree or wizard holding a staff. The more polygons you use on an object, the more detailed your finished images can become.
Each object has its own set of coordinates that can be set in a scene. For example, if a human were to draw a drawing of a dining room, we would use our own judgment as to where the table and chairs should be, or how close these objects should be to the wall.
A computer cannot make these assessment calls and needs coordinates for placement. That’s one of the reasons why sometimes things go really wrong in video games and you suddenly see an object in the sky.
Once the scene is set, the GPU starts to figure out the perspective based on where the “camera” is looking at the scene. A street fight, for example, will look very different if your character is standing on top of a parked bus looking out for the chaos, instead of stealing glances while crouching behind a overturned taxi. Again, there is a lot of math going on to figure out viewing angles.
After a little more refinement, the images take on the textures, shadows, color and shadows that make it all come to life.
All this graphics processing is super fast and requires heavy calculations, so a separate processing unit is needed in the first place.
The GPU is purpose-built for graphics processing, which requires a lot of math calculations done in parallel. That heavier focus on computation and parallel operations is why early Bitcoin advocates turned to platforms filled with GPUs to generate the math required to mine cryptocurrency coins. CPUs, meanwhile, are not that specialized and are more common.
You could technically rely on a CPU for the graphics, but it wouldn’t be efficient and the end result would never be that visually impressive. The CPU simply does not have the resources for most games. Your operating system, other programs and background processes are already running. It also helps to run the game with physics calculations, AI operations and other tasks.
Which GPU do you need?
Now you know the basics of what a GPU does and the different types out there. So, how do you know which one you need? When you play games on a desktop, you need a graphics card, and a whole world of reviews are available to help you pick the best one.
In general, make sure to get a graphics card that is suitable for the resolution of your monitor, such as 1080p, 1440p or 4K. Video game features are constantly advancing and require new hardware. This means that graphics cards become obsolete more quickly than other components. Desktop owners have to buy something released in the last two to three years.
Be very careful when gaming on a laptop. Many gaming laptops have discrete GPUs that are up to two generations old and cost as much (or nearly as much) as a laptop with a newer GPU.
If you’re focused on enthusiastic video editing, a powerful CPU is more important, but a discrete graphics card (even one that’s a few generations old) is also needed.
For all others, integrated graphics card is sufficient. You don’t need a graphics card for video streaming, basic web games, or even basic photo editing. Make sure your CPU actually has an integrated GPU. Otherwise, you might be in for a frustrating surprise when you try to boot up that new desktop build.
If you are curious, you can check which GPU you have on your Windows 10 PC.
RELATED: How to check which graphics card (GPU) is on your PC