What is the role of the processor in video games?

The role of the processor in video games is often overlooked and neglected because of the sacred graphics card. And yet it proves essential for running the most demanding games.

Source: Claire Braikeh for Frandroid

The processor (CPU) is often called the “computer brain» and it is not without reason that everything goes through this chip, which manages a huge variety of tasks on your machine. Whether it’s running your operating system, its interface, executing sets of instructions specific to certain uses, or running multiple applications, your CPU is the crossroads of everything you do on a computer.

In the context of video games, this is often neglected in favor of the graphics card (GPU), as the two components work together to provide a technically flawless gaming experience.

From CPU to screen

A video game engine cannot communicate directly with a graphics card and must go through the processor. Each image ( frame) is therefore generated from the code of this engine that sends instructions to the processor. These relate to the logic of the game, its rules, but also to the physics of objects or ballistics for shooting games, for example. We will see in more detail what tasks the CPU is specialized in in real time.

The processor prepares this data and tells the graphics card what this image should look like. It therefore sends commands to the GPU using the graphics API used by the video game (DirectX, OpenGL, Vulkan or even Metal for Mac). These commands are translated into a language that the GPU understands thanks to your graphics card driver, they are called draw calls .

Source: https://www.gamedeveloper.com/

Specifically: a draw calltells the graphics card to draw a series of triangles (the geometry or meshes ) on the screen while compiling a shadowspecific (texture, light, color). This data, which is first processed in your RAM, then goes to the video memory (VRAM) of your graphics card, which uses it to generate the final image. Your processor waits for the GPU to finish rendering before starting a new one. draw call .

A video game engine cannot communicate directly with a graphics card and must go through the processor. The latter is the basis of all images that your GPU generates.

Beware of the bottleneck

So you understand quite quickly that if your processor cannot quickly send these commands to your graphics card, it will be limited very quickly. In this situation you will then “ CPU limited“, your processor will not be powerful enough to utilize the full potential of your GPU, no matter how powerful it is.

On the contrary, if your graphics card turns out to be insufficiently powerful compared to your processor, it will not be able to process all this data. draw calls is sent to it, your game performance will therefore be limited by your GPU. We call this scenario “ GPU limited » (yes, it’s original).

An underperforming component can create a bottleneck

It is important to identify this bottleneck, the famous one bottleneck, to evaluate which component in your system needs to be changed. Some sites do this very well, such as Bottleneck Calculator, where you can indicate your configuration and view definition and tell you whether or not you are limited by any of the parts of your system.

The role of the processor in the game

In addition to these commands sent to the graphics card, the processor works behind the scenes to control the various systems of the game engine. Here is a summary of the tasks the CPU performs in real time:

  • Inputs/outputs: entrances of your various peripherals (keyboard, mouse, microphone).
  • Game Physics: The instructions behind dealing with physics in the game, such as water, particles, tissue, as well as gravity and even ballistics.
  • Sound Management: The CPU manages the activation of the various sounds in the game, as well as their spatial representation.
  • THE matchmaking: to find the part that suits you in an online game
  • NPC AI: The processor manages the artificial intelligence of the non-player characters and bots that appear in the game, naturally following the instructions of the game engine.

But beyond everything that concerns the logic of the game, the power of the processor has an impact in two categories that we wanted to highlight: the consistency of your frame rate per second and the ray tracing .

A more consistent frame rate

Although a processor has no direct influence on the frames per second a video game runs at (except when it does).CPU limitedof course), however, it guarantees a certain steadfastness in this frame rate.

A processor that’s underpowered for a graphics card can cause stuttering that won’t necessarily be reflected in your average frame rate per second simply because they’re too small.

This is why many benchmarks video games (including those from Frandroid) contain minimum values ​​of 1% and even 0.1%, which gives indications about the absolute bottom of your performance, in 1 and 0.1% of cases.

A well-chosen processor will allow you to maintain a consistent frame rate per second as the CPU and GPU operate at relatively the same level. You then have the choice to limit your FPS to mitigate this phenomenon or to lower certain graphics settings.

Ray tracing effects

If ray tracing technology, and by extension path tracing, is generally demanding on your graphics card, using it will systematically increase the usage of your processor.

This is mainly due to the fact that traditionally the CPU is responsible for the BVH algorithm ( Bounding volume hierarchies) that manages, very schematically, the collision between the different rays of a scene and the 3D volumes it contains.

Spider-Man Remastered // Source: Sony Interactive Entertainment

If this process has been accelerated by RT cores since the arrival of GeForce RTX, it can still exploit your processor’s resources.

This is the case for certain open mode games that offer options forray tracing as Spider-Man remasteredOr Cyberpunk 2077 . But other games, with radically different technical foundations, will shift all the load to the GPU Alan Wake2which uses very little of your CPU.

What kind of games is a powerful CPU useful in?

Now that we’ve seen the role of your processor during your gaming sessions, let’s take a look at the games that make the most intensive use of CPU resources.

These games, due to their operation, their logic and their graphical proposal, use your processor more than others.

Management and simulation games

Management games are naturally very demanding on the CPU. By simulating entire systems, numerous NPCs (non-player characters), their artificial intelligence and all economic systems, a management or city creation game will make use of instruction sets associated with your processor and generally most of your cores/threads.

Star Citizen // Source: Cloud Imperium Games

The combination of all these systems and the player’s actions that affect these systems are usually enough to put a heavy strain on your processor.

Examples of games: Star Citizen, Total War Warhammer 2, city skylines, civilization, Stellaris, endless space

Open world games

Open world games feature large environments that are usually filled with life and systems (weather, NPC routines, interactions, etc.). To make these worlds believable, it is up to the processor to calculate all the logic of the elements that populate these worlds (weather, physics, NPC routines, etc.).

Cyberpunk 2088 // Source: CD Projekt Red

And with the race for photorealism in recent years, these games are often very complex graphically, and therefore just as demanding on the GPU. Additionally, some of these games use procedural generation technologies for environments unique to each game, as well as their effects ray tracing, which may also require resources from your processor. In this category we include multiplayer games whose games take place in large environments.

Examples of games:Arma 3, Assassin’s Creed Odyssey, No Man’s Sky, Battlefield 2042, Cyberpunk 2077, Spider-Man Remastered…

Competitive FPS

AH good? Competitive FPS are CPU intensive? Not quite. These games run on engines that prioritize raw performance over graphical fidelity to give players a zero-latency experience.

Due to their graphics offering, they are not very demanding on your graphics card. To maximize your FPS in these types of games, you tend to lower all graphics settings, but also your definition.

Valorant // Source: Riot Games

Your graphics card will have no trouble generating a very large number of images at this display level. The onus is on your processor to send it sufficientlydraw callsto achieve the expected level of performance.

This is also why the test of a processor is carried out with low definition, because in this case it will have more work than your graphics card and it will be possible to assess its real impact on your frame rate per second .

Examples of games:Valorant, Counter-Strike 2, Apex Legends, Overwatch 2…

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