If you've built a gaming PC at any stage in your life, then chances are you've heard about games being CPU-bound or GPU-bound. Some games will benefit from CPU upgrades, and others will benefit from GPU upgrades, but why is that? Why is it that some games, no matter how much you tweak their settings, won't get any more performance? These are typically CPU-bound games, but there's more than meets the eye here.

What are CPU-bound games?

Games like Counter-Strike are considered CPU-bound

In simple terms, a CPU-bound game is limited by the processing power of the CPU rather than the GPU. When a game is CPU-bound, it means that the CPU is doing most of the work, handling tasks like physics calculations, AI, game logic, and even some rendering processes. The frame rate and overall smoothness of a CPU-bound game are typically tied to the CPU’s performance, which is why even powerful GPUs can sometimes struggle to improve frame rates in these types of games. Games like Counter-Strike are considered CPU-bound games, thanks in part due to the lower graphics complexity and physics.

CPU-bound games are often associated with titles that involve complex calculations and need to manage large amounts of data in real time. Strategy games, for example, with large numbers of units moving simultaneously or simulating complex economies, can often be CPU-bound because the game logic and AI require constant processing. Think games like Cities: Skylines. Open-world games with numerous NPCs, AI behavior, and background simulations also tend to be CPU-intensive, as the processor is tasked with managing the interactions and state of each entity within the game.

The challenge with CPU-bound games is that they can hit performance ceilings if the CPU isn’t fast enough to keep up with the game’s demands. Even if you have a powerful GPU, a game that’s constrained by a weak CPU will struggle with low frame rates, stuttering, or lag, because the processor simply can’t process enough data for the GPU to run at an equivalent pace. As a result, upgrading the CPU or focusing on games that are more GPU-bound might be the best option if you want a smoother experience and you've discovered that your CPU is a bottleneck.

What are GPU-bound games?

These are significantly more common

GPU-bound games, on the other hand, are limited primarily by the performance of the GPU. When a game is GPU-bound, the graphics card does the heavy lifting, managing the rendering of graphics, shadows, textures, and lighting. In these games, the CPU is not the main bottleneck for performance, which means you’ll see the most gains from upgrading your GPU or adjusting graphics settings rather than increasing CPU speed. Most games probably fall under the GPU-bound category.

Games that fall under this are visually intensive games such as open-world action games, some first-person titles, and racing simulators. Titles with high-resolution textures, ray tracing, and complex visual effects lean heavily on the GPU because it’s designed to handle the parallel processing needed for rendering graphics. In these cases, a stronger CPU won’t necessarily boost performance if the GPU is already maxed out. The game’s frame rate will likely improve only when the graphics card is upgraded or when you lower graphics settings that affect visual fidelity, such as shadow quality or texture resolution.

The benefit of understanding whether a game is GPU-bound is that it helps you know where to focus your hardware budget. If your goal is to play visually intensive games at the highest settings, investing in a powerful GPU will likely provide the best experience. On the flip side, upgrading the CPU won’t make a big difference in these types of games if your graphics card is the primary limiting factor.

How to tell whether a game is CPU or GPU-bound

Generally speaking, it won't be hard to find out

If you're trying to figure out whether a game is CPU or GPU-bound, the first step is generally just to find out what people are saying. Generally, you can get by with the data points that other people online will collect for you by sharing their experiences, but you can also test it yourself, too. The quickest way is to simply look at your system’s performance monitoring tools while playing. If your CPU usage is consistently at or near 100%, but your GPU isn’t, the game is likely CPU-bound. Conversely, if your GPU is maxed out while the CPU has headroom, you’re dealing with a GPU-bound game. Tools like MSI Afterburner, HWMonitor, or even the Windows Task Manager can give you real-time insights into resource usage.

However, there are other ways to find out, too. If lowering graphical settings doesn’t significantly improve performance, chances are the game is a CPU-bound game. When you reduce settings like shadows, textures, or anti-aliasing and see little to no gain in frame rate, your CPU is likely the bottleneck. However, in GPU-bound games, these adjustments should have a noticeable impact on performance, as they directly affect the workload on the GPU.

For many modern games, the performance bottleneck can also shift depending on the resolution that you're playing at. At lower resolutions, like 1080p, the CPU might become the limiting factor as the GPU has less work to do when rendering what's on screen. But at higher resolutions, such as 1440p or 4K, the GPU might be the bottleneck, as there is an exponential increase in pixel count as you scale up in resolution.

When building a PC though and needing to make a choice between the CPU or the GPU, what games you intend on playing matters. That's why you should do your research to see whether the games you want to play have a massive disparity in what's required, as you may even be able to save money in the case of some games if you don't need a particularly powerful CPU or GPU.