Video Card Unit

Current GPUs connect on the motherboard through the PCI x16 slot.

What is a Video/Graphics Card?

The images you see on your computer monitor are made of tiny dots called pixels. At most common resolution settings, a screen displays more than 2 million pixels, and the computer has to decide what to do with each one in order to create an image. To do this, it needs a translator -- something to take binary data from the CPU and turn it into a picture you can see. This translator is known as a graphics processor, or GPU.

Most entry-level consumer laptops and desktops now come with a secondary GPU built into their main processor (CPU), known as integrated graphics. Pro-level or custom machines, however, will often also have space for a dedicated graphics card. The advantage of a dedicated graphics card is that it can typically render more complex visuals much faster than an integrated chip.

A graphics card's job is complex, but its principles and components are easy to understand. In this article, we will look at the basic parts of a video card and what they do. We'll also examine the factors that work together to make a fast, efficient graphics card.

Think of a computer as a company with its own art department. When people in the company want a piece of artwork, they send a request to the art department. The art department decides how to create the image and then puts it on paper. The end result is that someone's idea becomes an actual, viewable picture.

A graphics card works along the same principles. The CPU, working in conjunction with software applications, sends information about the image to the graphics card. The graphics card decides how to use the pixels on the screen to create the image. It then sends that information to the monitor through a cable.

A draw call is a call to the graphics API to draw objects (e.g., draw a triangle), while a batch is a group of draw calls to be drawn together. Batching objects together minimizes the state changes needed to draw each object inside the batch.

Minecraft running on an RTX capable GPU. RTX is Nvidia's name for their Ray Tracing architecture.

Wireframe models for a video game.

Wireframe character with textures.

Creating an image out of binary data is a demanding process. To make a 3-D image, the graphics card first creates a wire frame model out of straight lines. Then, it rasterizes the image (fills in the remaining pixels). It also adds lighting, texture and color. For fast-paced games, the computer has to go through this process about 60 to 120 times per second. Without a graphics card to perform the necessary calculations, the workload would be too much for the computer to handle.

The graphics card accomplishes this task using four main components:

  • A motherboard connection for data and power

  • A graphics processor (GPU) to decide what to do with each pixel on the screen

  • Video memory (VRAM) to hold information about each pixel and to temporarily store completed pictures

  • A monitor connection so you can see the final result

Ray Tracing

What is ray Tracing? Well, it's an advanced and lifelike way of rendering light and shadows in a scene. It's what movies and TV shows use to create and blend in amazing CG work with real-life scenes. However, because ray tracing works by simulating and tracking every ray of light produced by a source of lighting, it kind of takes a lot of horsepower to actually render. This is the main reason we haven’t seen ray tracing implemented in actual games – until now.

These days, ray tracing is actually achievable in PC games, and yet the biggest titles to implement this technology only use it in limited ways, like rendering realistic reflections or shadows. We still haven’t seen a fully ray-traced game.

Ray tracing is a rendering technique that can produce incredibly realistic lighting effects. Essentially, an algorithm can trace the path of light, and then simulate the way that the light interacts with the virtual objects it ultimately hits in the computer-generated world.

We've seen in-game lighting effects become more and more realistic over the years, but the benefits of ray tracing are less about the light itself and more about how it interacts with the world.

Ray tracing allows for dramatically more lifelike shadows and reflections, along with much-improved translucence and scattering. The algorithm takes into account where the light hits and calculates the interaction and interplay much like the human eye would process real light, shadows, and reflections, for example. The way light hits objects in the world also affects which colors you see.

The GPU

Like a motherboard, a graphics card is a printed circuit board that houses a processor and VRAM. It also has an input/output system (BIOS) chip that stores the card's settings and performs diagnostics on the memory, input and output at startup.

A graphics card's processor, called a graphics processing unit (GPU), is similar to a computer's CPU. A GPU, however, is designed specifically for performing the complex mathematical and geometric calculations that are necessary for graphics rendering. Some of the fastest GPUs have more transistors than the average CPU.

A GPU produces a lot of heat, so it is usually located under a heat sink or a fan. Integrated chips differ slightly, in that they don't have their own VRAM, and have to pull from the same RAM stockpile as the CPU. This distinction may cause your system to run short on memory while gaming with an integrated GPU.

In addition to its processing power, a GPU uses special programming to help it analyze and use data. AMD and nVidia produce the vast majority of GPUs on the market, and both companies have developed their own enhancements for GPU performance. Today's video processors can provide:

  • Full scene anti-aliasing (FSAA), which smooths the edges of 3-D objects

  • Anisotropic filtering (AF), which makes images look crisper

  • Real-time physics and particle effects

  • Multiscreen displays

  • High frame rate video output

  • Ultra high-definition video with many millions of pixels

  • GPU-accelerated calculations

  • DLSS (nVidia) - real-time deep learning image enhancement and upscaling

  • FidelityFX (AMD) - an upscaling technology that makes for one of the easiest ways to boost fps in supported games.

Each company has also developed specific techniques to help the GPU apply colors, shading, textures and patterns.

As the GPU creates images, it needs somewhere to hold information and completed pictures. It uses the card's RAM for this purpose, storing data about each pixel, its color and its location on the screen. Part of the VRAM can also act as a frame buffer, meaning that it holds completed images until it is time to display them. Typically, video RAM operates at very high speeds and is dual ported, meaning that the system can read from it and write to it at the same time.

Modern video cards plug into a PCIe x16 expansion slot. Small form-factor computers with integrated graphics, such as laptops and mini desktops, may not come with such a slot. Graphics cards can still be connected, however, using a costly workaround device called an external GPU.

The Evolution of Graphics Cards

Graphics cards have come a long way since IBM introduced the first one in 1981. Called a Monochrome Display Adapter (MDA), the card provided text-only displays of green or white text on a black screen. Now, both graphics cards and integrated chips can easily send out an HD (1,920 x 1,080 pixel) signal through an HDMI or DisplayPort cable. Standalone cards often put out Ultra HD 4K (3,840 x 2,160) video, with even higher resolutions available on higher spec GPUs.

Choosing a Good Graphics Card

A top-of-the-line graphics card is easy to spot. It has lots of memory and a fast processor. Often, it's also more visually appealing than anything else that's intended to go inside a computer's case, and will cost significantly more than a mid-range card. Lots of high-performance video cards are illustrated or have decorative fans or heat sinks.

But a high-end card provides more power than most people really need. People who use their computers primarily for email, word processing or social media can find all the necessary graphics support on a CPU with integrated graphics. A mid-range card is sufficient for most casual gamers. People who need the power of a high-end card include gaming enthusiasts and people who do lots of 3-D graphic work.

A good overall measurement of a card's performance is its frame rate, measured in frames per second (FPS). The frame rate describes how many complete images the card can display per second. The human eye can process about 25 frames every second, but fast-action games require a frame rate of at least 60 FPS to provide smooth animation and scrolling. Components of the frame rate are:

Triangles or vertices per second: 3-D images are made of triangles or polygons. This measurement describes how quickly the GPU can calculate the whole polygon or the vertices that define it. In general, it describes how quickly the card builds a wire frame image.

Pixel fill rate: This measurement describes how many pixels the GPU can process in a second, which translates to how quickly it can rasterize the image.

The graphics card's hardware directly affects its speed. These are the hardware specifications that most affect the card's speed and the units in which they are measured:

  • GPU clock speed (MHz)

  • Size of the memory bus (bits)

  • Amount of available memory (MB)

  • Memory clock rate (MHz)

  • Memory bandwidth (GB/s)

The computer's CPU and motherboard also play a part, since a very fast graphics card can't compensate for a motherboard's inability to deliver data quickly. Similarly, the card's connection to the motherboard and the speed at which it can get instructions from the CPU affect its performance.

Signs of a Dying GPU

Windows Blue Screen of Death (BSOD)

Here are a few problems you might run into with a failing GPU.

  • Graphical Glitches Gradually Worsening - Graphical glitches are mainly spotted in games, manifesting in the form of poorly-loaded textures, screen glitches, screen tearing, or random artifacts appearing on your screen mid-game.

  • Strange Fan Noise - You'll know if your GPU's fans are dying if they emit a strange noise while they're running under load, or if one or more (most GPUs come with two or even three fans) straight up stops working.

  • Crashes Galore - Another piece of evidence that your GPU might be slowly trying to reach its grave is if your PC is crashing and rebooting more frequently than usual during games or while watching movies.

  • Significant Frame Drops - When you're playing a game, if you notice it's running at 10 FPS instead of the usual 60 FPS, it could be a bad sign for your GPU's health. You'll need to rule out other things before ensuring the actual GPU is the culprit. Specifically, you should rule out that the GPU is thermal throttling. Test your graphics card's temperatures; if they're too high, you should go back to point number two (Strange Fan Noise) and check if your GPU fans are working correctly. If temperatures seem fine yet performance is still awful, this may mean disaster.

  • Blue Screen of Death - Finally, the ultimate warning that something is seriously wrong with your computer: the blue screen of death. At least, that's how it presents on Windows. It can come up for any reason, and yes, it can also come up if your GPU is going bad, and other operating systems present critical errors different from Windows.