A processor, motherboard, fast memory, a graphics card that flies, a couple of SSDs, a quality power supply, lots of RGB, and that's it: Your gaming PC is complete. However, when you start measuring FPS and frametime, you discover that component utilization is not ideal. Why does that happen? Most likely you're witnessing a PC bottleneck. Today we'll explain what it is and what you can do to reduce its effects.

Why Does the PC Bottleneck Exist?
PC bottleneck

The PC Bottleneck: A Long History

Although it seems unbelievable, the concept of a PC bottleneck is not new, and most users have already experienced it firsthand. For decades, storage units (hard disks, floppy disks, etc.) were and still are the limiting factor for millions of computers.

Why Does the PC Bottleneck Exist?
Conventional 5,400 RPM hard drives are the bottleneck in millions of laptops.

With solid-state technology and the NVMe specification, this situation has greatly improved, but the bottleneck has moved to other components, more specifically the processor (CPU) and graphics card (GPU).

Why Do We Have Bottlenecks?

The most popular explanations always invite us to visualize bottles filled upside down or hourglasses, but in relaxed terms we can say that the bottleneck arises when a component in the computer must wait for another component to finish its work.

  • CPU bottleneck: Suppose you've upgraded your graphics card without changes to the CPU. The new GPU is too powerful and cannot reach its full potential because the processor doesn't keep up. The GPU renders frames faster than the CPU can prepare them, and its only option is to wait, causing “underutilization” of the graphics card. (Extreme example: A GeForce RTX 3090 paired with a Ryzen 3 3100)
  • GPU bottleneck: The same, but in reverse. When a multi-core processor with many threads is installed alongside a relatively small graphics card, the GPU stays glued at 99 or 100 percent utilization, while the processor's threads “sleep” in the background, or record very low activity. However, the GPU bottleneck is not so negative. (Extreme example: A Core i9-10900K with a GeForce GTX 1050 Ti)
Why Does the PC Bottleneck Exist?
In the image, a GeForce RTX 3090. Many users try to eliminate bottlenecks with brute force, but high-end hardware must be well accompanied.

Which One Is Preferable?

In an ideal world, none. Your goal is a balanced system, with CPU and GPU working efficiently and coordinated. But if you have to choose a poison, all arrows point to “a little” GPU bottleneck. Why? Because what we see on screen is the product of the GPU, and if its utilization is at 100 percent, then it's already putting everything on the table, rendering every frame it receives without exception.

Can You Calculate a Bottleneck?

Why Does the PC Bottleneck Exist?
Online calculators help, but they don't have the last word. You'll need something like MSI Afterburner to detect bottlenecks.

To a certain extent. One of the most popular resources is The Bottlenecker, now called Bottleneck Calculator. All you have to do is enter your components, the amount of RAM, and let the site do its work. But The Bottlenecker doesn't have the last word by any means. All confirmation needs more advanced tools, and at the top of the list is MSI Afterburner, with real-time FPS, frametime, and component utilization measurements.

Why Does the PC Bottleneck Exist?
MSI Afterburner is a fundamental resource for detecting PC bottlenecks and getting the most out of your graphics card.

How Can You Minimize a PC Bottleneck?

If the bottleneck is on the CPU, the first (and most economical) thing is to reduce its load. Less is more. Close active applications and processes, or use more efficient software. In other words, the game doesn't need competition. If Chrome stays in the background with 25 tabs or you have sync software activating every five minutes, try closing all that. A better use of the CPU automatically leads to a better use of the GPU, so the benefit is double.

Why Does the PC Bottleneck Exist?
If the GPU is modest but there's plenty of firepower in the CPU, disabling hardware acceleration in certain applications could help.

A well-applied overclocking can also be useful. Sometimes the processor or GPU just needs an extra push, and if the rest of the computer has a robust configuration (read: good motherboard and a strong power supply), a pinch of overclocking could balance the scales. Another possibility to explore is disabling hardware acceleration in certain applications. The most talked-about case is Discord: its own developers recommend this step if you notice a loss of frames with the messenger open.

In Summary: Take It Easy

Why Does the PC Bottleneck Exist?
The PC bottleneck is not eliminated with a couple of clicks. There are many factors at play.

Understanding a PC bottleneck is simple. Balancing all related aspects, not so much. CPU, GPU, drivers, RAM, video memory, graphical quality and resolution, the technical details of each game (it's not the same an MMO as an offline single-player RPG), overclocking, undervolting, cooling and temperature... the list is long. As PC gamers we understand that we will never get perfect results, but at the same time we are more than willing to face the challenge. Do you think you have a bottleneck in your PC? Leave a comment!