How is the video card (GPU) working? (ELI5)

For your computer to determine which pixels on your monitor should display, what color, and at what time, it must perform an enormous number of calculations in milliseconds. Modern computers accomplish this task using a graphics card—a term many are familiar with, but few fully understand.

A graphics card is a specialized computer designed only to display images on your screen, especially three-dimensional ones. Like your computer, it has a processor called the GPU (Graphics Processing Unit).

GPU vs CPU:

Similar to how the CPU is to your computer, the GPU is to your graphics card. The key difference between a CPU and a GPU is the number of cores for each processor. Like small calculators, processor cores perform the calculations your computer needs to run very quickly. Today's graphics card can contain anywhere from 1,000 to 7,000 cores, while a modern home-based CPU usually has six to eight cores.

Although a CPU's core count is lower than a GPU's, each one is much more powerful. This allows CPUs to perform more demanding jobs, like breaking down logic and carrying out commands. Nevertheless, even though CPU cores are more powerful, they can only manage a single task simultaneously.

When it comes to following instructions, this singular attention is sufficient. However, rendering tasks are simple but require numerous tasks at once. As a result, rendering graphics on a CPU would cause a bottleneck, causing processes to queue up and process slowly, while a GPU can perform this job rapidly faster.

A CPU can handle a few very complex tasks simultaneously, while a GPU can simultaneously manage thousands of more straightforward tasks.

Explain like I'm 5 (ELI5):

Consider an example of a person with twenty smaller arms and another with two strong ones. The individual with the strong arms is the best choice if you need to lift a heavy object. However, if twenty light objects need to be lifted, the one with more arms is more productive. Carrying out several objects at once is essential for creating a three-dimensional visual representation. That's why we chose GPU (a person with more arms) to handle the task.

Video card for 3D:

When computers create 3D worlds, they use something called vector graphics. This involves plotting coordinates in a three-dimensional space, drawing a graph, and then connecting these points with lines based on mathematical calculations—similar to what you might remember from geometry class. Every object and shape in 3D graphics boils down to this: determining the relative positions of points and the curvature of lines between them, all of which are math-intensive tasks.

GPU for cryptocurrency mining:

This capability is also why GPUs are so effective in cryptocurrency mining. For example, the type of calculations required for Bitcoin mining are better suited to many small cores rather than a few powerful ones.

Because a graphics card functions like its own mini-computer, it has its own processor (the GPU) and its own RAM, often called video RAM or VRAM. Like the main RAM in your computer, VRAM stores small amounts of easily accessible data. During the image creation process, some data types are critical and must be accessed frequently. The RAM in your graphics card stores this data and supplies it to the GPU as needed.

These are the basics of how and why a graphics card works. Understanding this helps clarify why GPUs are indispensable for tasks that involve heavy graphical computations or specialized operations like cryptocurrency mining.

If you're interested in learning more about graphics cards, please check more articles on this topic: Everything you Need to Know About NVIDIA Ampere A100

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