Understanding the Different Roles of your CPU and GPU in Gaming – BattleNub Explains

Introduction

In the world of computer hardware, two components often take center stage when it comes to gaming performance: the Central Processing Unit (CPU) and the Graphics Processing Unit (GPU). Many gamers who build their own custom PCs understand the importance of these two components, but not all of them know their significance, or the impact of making the right or wrong choice when purchasing specific parts. Understanding the distinction between these two can help you make more informed decisions when building or upgrading your gaming PC.

The Role of the CPU vs the GPU

The CPU

Often known as the computer’s brain, the CPU excels in general-purpose computing. It’s primed for tasks demanding high single-threaded performance such as running applications and carrying out computations sequentially. The CPU processes these tasks rapidly, one after another, creating an illusion of simultaneous operations.

The ELI5 version: Visualize the CPU as an efficient office worker that is skilled at rapidly completing a long list of tasks. For instance, it may first calculate a complex Excel formula (like doing your math homework), then load a Word document (like reading a book), and finally manage files in the file explorer (like cleaning your room). It processes these tasks sequentially yet so swiftly that it appears to be doing everything at once.

Here are a few concrete examples of tasks your CPU performs:

1. Running Your Operating System: Your CPU is what allows your operating system—whether it’s Windows, MacOS, or Linux—to run. It processes the instructions that allow you to interact with your computer’s interface, open and close windows, and adjust system settings.
2. Running Applications: Whether you’re typing a document in Microsoft Word, browsing the web on Chrome, or editing a photo in Photoshop, your CPU is what makes that possible. It processes the commands you input through your mouse and keyboard, and it tells the rest of your computer’s hardware what to do based on those commands.
3. Performing Calculations: If you’re using your computer for work or school, you might be running software that requires complex calculations, like a CAD program for 3D modeling or a financial analysis tool. Your CPU is what performs those calculations.
4. Multitasking: If you have multiple applications open at once, your CPU is what allows you to switch between them without having to close and reopen each one. It keeps track of where you left off in each application, so you can pick up right where you left off.

The GPU

Conversely, computer architects build a GPU for parallel computing. With hundreds or even thousands of cores comprising a GPU, it can efficiently handle thousands of threads simultaneously. This design makes it particularly useful for tasks like rendering graphics, where it needs to perform the same operation on many pixels or vertices simultaneously.

The ELI5 version: Think of the GPU as a team of construction workers building a skyscraper. Each worker is responsible for a different task (pouring concrete, installing windows, wiring electricity), but they all work together at the same time to complete the building. In the same way, the GPU’s many cores all work together to render graphics, perform computations for AI, or analyze data.

Here are some practical examples of tasks that a GPU performs:

1. Rendering Graphics:. Whether you’re playing a game, watching a video, or using a virtual reality application, your GPU is what translates data into the pixels you see on your screen. It calculates how each pixel should look based on lighting, color, texture, and other factors.
2. Performing Computations for Science: GPUs are often used in fields which require many calculations to be performed at once, sometimes with large amounts of data. Fields such as artificial intelligence (AI) and machine learning, benefit from the simultaneous calculations. While finance and other fields of science with large amounts of data can be parsed much more quickly with GPUs as opposed to other types of processors.
3. Creating Special Effects: GPUs are also used to create special effects in video production and 3D rendering and animation. Their ability to perform many calculations simulataneously fills the requirements needed to create realistic lighting, shadows, textures, and other visual effects.

CPU and GPU in Gaming

The CPU

In gaming, the CPU plays a critical role in ensuring everything runs smoothly and as expected. Here’s a breakdown of its responsibilities:

1. Game Logic: The CPU is responsible for the ‘rules’ of the game. It’s what ensures that a game behaves the way designers intended them to. For example, in a strategy game, the CPU might be responsible for managing resources, controlling non-player characters, or determining the outcome of battles based on the game’s rules.
2. Physics Calculations: In many games, realistic physics are crucial to the gameplay experience. The CPU might be responsible for calculating the trajectory of an arrow in a bow-and-arrow game, the force of an explosion in a first-person shooter, or the gravity in a space exploration game.
3. AI Behavior: In games with lots of NPCs, the CPU often controls the behavior of AI opponents. This might involve determining their movements, reactions, or strategies based on the player’s actions and the game’s rules.
4. Input Processing: Every time you press a button or move your mouse, your CPU is what translates that input into an action in the game.
5. Sound Processing: The CPU may be responsible for triggering sound effects at the right time or adjusting the volume based on the player’s location in the game world.
6. Preparing Data for the GPU: One of the CPU’s most important roles in gaming is preparing data to be sent to the GPU. This might involve determining which objects need to be rendered and from what perspective. For example, the CPU would determine which parts of the game world are currently visible to the player and need to be rendered by the GPU in a game like TES: Skyrim or The Witcher 3.

The GPU

The GPU is the powerhouse of graphics rendering, taking on the heavy lifting when it comes to creating the visuals in your game. Here’s a deeper dive into its responsibilities:

1. Determining Pixel Color and Rendering 3D Objects: Perhaps the most fundamental task of the GPU is determining the color of each pixel on your screen. This involves considering the color and texture of the 3D objects, the lighting conditions, and the perspective from which you’re viewing them. For example, imagine a scene in a game where you’re standing in a forest at sunset. The GPU is what calculates how the light from the setting sun changes the color of the trees, the shadows cast by the trees, and the way the light reflects off a nearby river.
2. Creating Special Effects: Many of the special effects you see in games are created by the GPU. This includes effects like fog, reflections, shadows, and particle effects (like fire or water). The GPU calculates how these effects look in real time, allowing them to change in response to what’s happening in the game. The most talked about effect you may have heard about is ray tracing.
3. Texture Mapping: Textures are the visual details that make the objects in a game look realistic. They’re like the paint that’s applied to the 3D models created by the GPU. Texture mapping is the process of applying these textures to the models.
4. Post-Processing: After the GPU has finished creating the basic image that will be displayed on the screen, it can also perform additional post-processing effects to enhance the image. This might involve adding motion blur, adjusting the colors to create a specific mood, or applying a depth of field effect to make the scene look more realistic.

Balancing CPU and GPU Capabilities

When balancing the power of their CPU and GPU on a tight budget, many PC builders are uncertain about which component to prioritize and to what extent they can downgrade on one over the other.

High-End CPU, Low-End GPU Scenario

Investing in a high-end CPU while skimping on the GPU may seem like a cost-saving measure, but it can cause significant issues for gamers.

1. Bottlenecking: This is a common term you’ll hear when discussing PC builds. In this scenario the CPU processes game data at a high rate, but the GPU can’t render the corresponding graphics quickly enough. This discrepancy can lead to stuttering or lagging gameplay, as the GPU struggles to keep up with the CPU.
2. Reduced Visual Quality: A low-end GPU may not be able to handle high-resolution textures and complex visual effects. This limitation could force you to play games at lower settings to achieve smooth gameplay. Even with a high-end CPU, the visual quality of your games will be limited by what your GPU can render. Additionally, Some modern games lean heavily on GPU-intensive features like real-time ray tracing. With a low-end GPU, you may have to turn off these features, resulting in a less immersive gaming experience.

Low-End CPU with a High-End GPU

Even with a high-end GPU, pairing it with a low-end CPU can create its own set of challenges. Here’s what could happen in this scenario:

1. Bottlenecking: In this case, the bottleneck happens because the CPU can’t keep up with the GPU. The GPU, ready and waiting with its high-performance capabilities, finds itself idling while it waits for the CPU to send it instructions. This results in lower frame rates and potential stuttering during gameplay, even if your GPU is capable of much more.
2. Limitations on Game Types: While the GPU may be able to handle graphically-intensive scenes smoothly, strategy games, simulation games, or multiplayer online games often require a lot of CPU resources because they have to handle complex AI, physics, or multiple players’ actions. This inconsistency can make for a frustrating gaming experience.

Investing in a high-end GPU is a great move for gaming, but it needs to be paired with a capable CPU to get the most out of your investment.

Finding Balance

To achieve your PC building objectives without overspending, let’s outline the steps that can guide you towards making informed final decisions.

1. Identify Your Needs: Make a list of the games you want to play and applications you want to run with your new system.
2. Research Hardware Requirements: Once you know what you’ll be using your PC for, you can research the hardware requirements for the software or games you’ll be using. For games, you can usually find the minimum and recommended hardware requirements on the game’s website or on a digital distribution platform like Steam. Minimum requirements will allow you to play the game smoothly on low-medium settings, where as recommended requirements will allow you to push the graphical settings while still maintaining decent performance.
3. Choose a CPU and GPU within Your Budget: Start by looking at CPUs and GPUs that meet the recommended requirements for the software or games you’ll be using. Compare the prices and performance of different models. Remember that it’s better to have a balance between CPU and GPU performance rather than having one component that’s much more powerful than the other.
4. Check for Compatibility: Before you make a final decision, make sure that the CPU and GPU you’re considering are compatible with each other and with your other components. For example, make sure your power supply can provide enough power for your CPU and GPU, and ensure that your case has enough space to fit your GPU.
5. Consider Future Needs: If you can afford to, it might be worth spending a bit more to get a CPU and GPU that exceed your current needs. This will give you some room to grow into your PC and will make it more likely that your PC will be able to handle new software or games that come out in the future.
6. Read Reviews: Before making a final decision, read reviews of the CPU and GPU you’re considering. This can give you an idea of the real-world performance of these components and can help you avoid potential issues.

Remember, the goal is to find the best balance of performance and price that fits your specific needs. It may take some time and research, but the end result will be a PC that’s perfectly suited to your needs.

Conclusion

In the end, it’s crucial to remember that CPUs and GPUs are designed for different kinds of tasks. CPUs are optimized for sequential tasks, while GPUs are optimized for parallel tasks. To get the best gaming performance, it’s important to have a balanced system where the CPU and GPU complement each other, rather than one significantly outperforming the other.

Share Your Thoughts

What are your thoughts on multi-GPU setups? Do you have any experience with them that you’d like to share? Your insights can be a great help to others who are contemplating a similar decision.

Additionally, I’m always looking for new topics to cover in my blog. If you have a question about custom PC builds, or if there’s a specific topic you’d like me to delve into, please let me know in the comments section below via my contact form. Your question could be the inspiration for our next blog post!