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What is Bottlenecking? How Do I Fix It?

In this post, we’ve covered the basics of bottlenecking, why it is a concept you should be aware of, and how to prevent it from occurring in your PC.

If you’ve ever sought PC building advice, you’ve probably heard someone mention ‘bottlenecking’, and that it’s something you should prevent. Even some of the best gaming PCs can suffer from a bottleneck if you don’t choose all your components carefully – and make no mistake, there are many components that can bottleneck the rest of your rig.

A bottleneck occurs when one component in your gaming PC runs so much slower than the others that it limits other components’ capabilities. This is why, if you want a great, all-round gaming PC, you shouldn’t skimp out on any core component, whether that’s one of the best graphics cards or one of the best CPUs.

It’s also why you shouldn’t go too overboard with just one of your component upgrades – there’s no point buying an Intel Core i9-12900K just for gaming while you’re still running a graphics card that’s five generations old. Similarly, there’s little point upgrading your graphics card if the games you play are already limited by your CPU. The good news is preventing a bottleneck isn’t too difficult, and if you want to know how to prevent it we have you covered.

What is Bottlenecking?

The narrowest point of a bottle is its neck. There’s plenty of liquid inside the bottle itself, but congestion occurs while travelling through the narrow neck, and so the bottle’s output is limited by this single point of congestion. This is a metaphor for PC bottlenecking.

What is Bottlenecking?
The image above illustrates a bottleneck. The outflow of contents (from left to right) is held back by the restricted middle section.

PC bottlenecking occurs when one component acts like the neck of a bottle, limiting the PC’s overall capabilities. For example, if your PC boasts a top-tier CPU but it only has an old, relatively weak graphics card, your framerates when gaming will be ‘bottlenecked’ by this graphics card. Your PC’s potential performance is limited by the graphics card, because if it had a better graphics card your other components could utilise all their potential to push out more frames.

Preventing a bottleneck means making your PC more like a tube than a bottle: all components should be roughly equally matched in terms of their performance potential, meaning no single component limits the others components’ potentials.

How to Prevent a CPU Bottleneck

A CPU bottleneck occurs when your CPU isn’t powerful enough to allow other components to reach their full potential. Today, most mainstream CPUs won’t bottleneck a system for gaming, because modern games are very GPU-bound. For instance, even an Intel Core i3-10105 or AMD Ryzen 3 3300X CPU shouldn’t bottleneck low-end or midrange graphics cards and will only moderately bottleneck high-end ones in most games.

But if you’re looking to play modern games with very minimal bottlenecking, you should look for a midrange or high-end CPU. CPUs like the Intel Core i5-12600K or the AMD Ryzen 5 5600X are more than powerful enough to quell any doubts about bottlenecking while playing most games, even when paired with a high-end card like NVIDIA’s GeForce RTX 3080.

Where most modern games rely more upon the GPU, Civilization relies heavily on the CPU. For a game like Civilization, you may experience a CPU bottleneck if you don’t have a strong processor.

However, there are some very CPU intensive games, such as Civilization 6 and Assassin’s Creed: Origins. If you play lots of games like this, a high-end CPU like the Intel Core i9-12900K or AMD Ryzen 9 5900X will be a worthwhile investment to prevent a CPU bottleneck.

If you’re wondering whether your CPU is currently bottlenecking any of your games, load each game up alongside GPU and CPU monitoring software such as HWMonitor64, MSI Afterburner, or HWiNFO. Check your CPU utilisation and GPU utilisation while gaming, and if your CPU utilisation is very high or maxed out but your GPU utilisation has a fair amount of headroom, you’re probably dealing with a CPU bottleneck and could consider an upgrade.

How to Prevent a GPU Bottleneck

The component that most commonly bottlenecks a gaming PC is the graphics card. This is because modern games are often so graphically intensive that even the best graphics cards become heavily utilised on max settings, while the CPU is often being less utilised.

This is especially the case once you move down from high-end and into midrange component territory. If you have a midrange CPU and GPU combo, a GPU bottleneck will be more likely than a CPU bottleneck because midrange CPUs are often pushing close to a game’s maximum required complex processing power, whereas simple GPU geometry rendering, for example, can always be done much quicker in principle.

This means that significant GPU upgrades will almost always net you better performance in games, whereas the margins are slimmer with modern CPU upgrades. As such, you should often make your graphics card a priority in a new build or an upgrade. But if – perhaps because of the current chip shortage – you can’t afford something top tier, don’t worry, because your graphics card might not be bottlenecking your CPU.

Your GPU is probably only bottlenecking your CPU if it’s at very high or maximum usage in games, and you can check for this by using the hardware monitoring software mentioned above. If this is the case, and if your CPU utilisation is a lot lower, your GPU is probably acting as a bottleneck, and you can consider upgrading. Given how GPU-bound most games are, it’s rarely a bad idea to upgrade your graphics card anyway, because doing so is the single best way to squeeze extra gaming performance out of your machine.

How to Prevent a RAM Bottleneck

A RAM bottleneck is usually the easiest one to spot, because if you don’t have enough RAM your games will run slow and even potentially stutter or freeze. When you don’t have enough RAM for a game, reading and writing starts to take place via the HDD or SSD, and even one of the best SSDs doesn’t come close to the storage access speed of RAM.

As a rough guideline, 4GB RAM is too little for most games these days, and while 8GB can be fine in some games with few background processes running, 16GB is a much safer bet. This is because your PC will likely use over 10GB RAM when gaming, especially if you have other apps open, but it’s unlikely to reach 16GB RAM utilisation unless you’re running many background processes. 32GB is overkill for gaming unless you’re running simulators like Microsoft Flight Simulator, or you have some memory-intensive apps running in the background.

To check if you have a RAM bottleneck, just load up Windows Task Manager while you play and check the ‘performance’ tab. If your RAM utilisation is maxing out, or is very close to doing so, you might need more RAM capacity to prevent a bottleneck.

And while this is less important than ensuring you have enough RAM capacity, you should also pay attention to your RAM speed and timings, especially if you have a CPU that is very reliant on this. AMD Ryzen CPUs, for example, tend to get a hefty performance boost from higher RAM speeds and lower RAM clock timings. The best way to see the extent to which your CPU is affected by RAM speed and timings is to check benchmarks for your CPU that compare how it performs at different RAM speeds.

Quick Tips to Prevent a Bottleneck

So that’s the long story, and here’s the short:

  • To check if you have a CPU or GPU bottleneck, play some games while running a hardware monitoring program. If your CPU or GPU utilisation is maxed out while the other component has lots of headroom, the component that’s maxed out is bottlenecking.
  • To see whether your RAM is bottlenecking, check its utilisation in the Task Manager while gaming. If it’s maxed out, you have a RAM bottleneck.
  • The best way to prevent a bottleneck is to upgrade any component that’s bottlenecking so that it doesn’t limit the potential of other components.
  • If there’s only a slight GPU or CPU bottleneck, you can try overclocking the GPU or CPU to gain some extra performance, but this probably won’t give you a dramatic boost.
  • If you don’t want to upgrade, there are some things you can do to try and increase your FPS in games and offset a bottleneck. For instance, you can lower your graphics settings, enable DLSS or FidelityFX Super Resolution, or disable background processes that might be eating up resources.

So, there are things you can do to try and offset a slight bottleneck – mainly, reducing the required processing load by lowering your graphics settings and resolution. But if the bottleneck is severe, or if you don’t want to cut corners, your best bet is to upgrade the limiting component. Remember to keep an eye on your components’ utilisation levels to make sure a single component doesn’t hold back the rest of your build.

Jacob Fox

Jacob's been tinkering with computer hardware for over a decade, and he's written hardware articles for various PC gaming websites. Outside of the wonderful world of PC hardware, he's currently undertaking a PhD in philosophy, with a focus on topics surrounding the meaning of life.