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CPU and GPU Bottlenecks: Everything You Should Know

Whenever you’re in a discussion about PC performance, but especially PC gaming performance, you may hear about something called a GPU bottleneck. GPU and CPU bottlenecks are referred to as a scourge to in-game framerate, but what does all this stuff actually mean?

More importantly…how can you fix it?

CPU and GPU Bottlenecks Explained

What is a bottleneck?

In the context of hardware, a bottleneck refers to a component in your system that’s holding back the performance of another (or every other) component in your system. For instance, a 5400 RPM hard drive slapped into the world’s most powerful gaming PC would be a significant bottleneck, since it would result in woefully slow in-game load times and in-game performance hitching due to assets being loaded in late.

If you want to ensure consistent in-game performance, removing bottlenecks from your system is vital.

What is a GPU bottleneck, and how do I fix it?

When most people talk about bottlenecks, this is usually what they’re referring to- GPU bottlenecks.

Unfortunately, there are only two ways to fix a GPU bottleneck:

  • Lower your in-game settings to achieve your desired framerate (if you’re in this situation, we recommended turning off AA and post-processing first, as well as changing any “Ultra” settings to “High”)
  • Replace your current GPU with a new GPU

GPU bottlenecks are tied firmly to in-game graphical fidelity and settings. However, many gamers prefer to focus on raw playability and fluidity instead of pretty graphics. For these players, making the game look like it could run on a Nintendo 64 is worth it, so long as they achieve super-high framerates (120+) that give them a competitive advantage.

Unfortunately, even those gamers can’t do much about what’s up next…

What is a CPU bottleneck, and how do I fix it?

A CPU bottleneck is, generally-speaking, much worse to deal with than a GPU bottleneck. The reason why is simple: short of actually replacing your CPU, almost nothing can be done about a CPU bottleneck.

The vast majority of in-game graphics settings have nothing to do with your CPU, and the ones that do- like View Distance in Fortnite- have gameplay implications. Turning down a setting like View Distance in a competitive multiplayer game could give you a very real disadvantage against other players.

So, why are CPU bottlenecks such a big deal?

Why CPU bottlenecks are more complicated- and arguably more important

Simply put: your CPU is the real bottleneck, in any scenario. What your graphics card is doing is making all the pretty graphics on your screen. What your CPU is doing is all the actual work, like tracking the position of players and objects at any point in time, and all the other millions of calculations required for real-time gameplay. All the actual game logic stuff is happening on your CPU, not your GPU.

To sum up what we’re saying, put this to memory:

While your GPU determines your maximum possible graphical fidelity, your CPU determines your maximum possible framerate

According to many third-party studies, higher framerates provide both better perceived fluidity (provided your monitor’s refresh rate can keep up) and in-game player performance. If you’re interested in a more in-depth look at how high refresh rate and framerate impact player performance, we recommend watching the video embedded below:

[Note: While the study is sponsored by Nvidia, any competitive FPS player will tell you the same thing regarding higher refresh rates improving performance. High refresh monitors are standard in eSports for this reason!]

Other bottlenecks to think about

When it comes to bottlenecking, the CPU and GPU aren’t all you need to think about. You also have to consider…

Memory Bottlenecks

Memory, or RAM bottlenecks! Technically, this kind of acts as a CPU bottleneck too.

Your RAM speed is tied to your CPU performance, especially if you’re using an AMD Ryzen CPU. The biggest way that RAM speed negatively impacts performance isn’t by users not buying the most high quality gaming RAM or anything, though.

The issue is that many users are running in single-channel, instead of dual- or quad-channel RAM configurations.

“Single-channel” RAM refers to RAM run with a single stick, which restricts it to running at half of its rated speed.

“Dual-channel” RAM refers to running dual RAM sticks, which allows it to achieve its rated speeds.

“Quad-channel” RAM refers to running…quad RAM sticks, though this doesn’t double rated speeds. It still provides an improvement over dual-channel, though, and may be ideal for any RAM-speed reliant tasks you’re running.

When it comes to gaming, it doesn’t really matter if you’re running in dual or quad-channel. However, it’s important that you aren’t running in single-channel, as this will greatly compromise your CPU’s effective speed (especially with Ryzen!) and result in you not getting all of the performance you paid for.

If you care about avoiding CPU bottlenecks and getting the best performance, always run your RAM in dual channel!

Storage Bottlenecks

Storage bottlenecks aren’t usually a concern, but can become a problem with particularly slow or aging hard drives.

A modern standard 7200 RPM HDD you’ve owned for a year or two should be fine in this regard. It won’t be as blazing fast as an SSD in terms of loading times, but as long as it doesn’t hitch when loading assets or anything, you’re probably fine.

Where you will encounter issues is with aged or slow (5400 RPM) HDDs. As they start to deteriorate, you may notice your games having issues loading in all their textures and assets. In severe cases (like with Overwatch), your drive speed may be so slow that you’re unable to load the map in time to join the game.

For the best experience, we recommend getting an SSD for gaming.

How to avoid CPU bottlenecks in your next PC build

So…now that we’ve gone through everything, how do you avoid this CPU bottleneck issue in the future?

We’re going to boil it down to some very simple PC builders’ advice. Follow these points, and you will be just fine:

  • Don’t skimp on your CPU! – While you may be tempted to spend far more on a GPU than your CPU, don’t. Your GPU is much easier to replace in the future than your CPU is, and the price-to-performance ratio over time improves much more with GPUs than CPUs. Get a great CPU today and a great GPU tomorrow.
  • Get a CPU with strong single-core performance – Any modern Ryzen 5 or Intel Core i5 processor should do the trick. Stick with the latest architecture to get the best single-core performance from either manufacturer. At the time of writing, Intel has a slight lead here, so consider them if you have the extra money or intend on pushing super-high frames (150+) in cutting edge games.
  • Get a Dual-Channel RAM kit – To ensure your CPU doesn’t get bottlenecked by your RAM, get dual-channel RAM, especially if you’re using Ryzen.
  • (optional) Get an SSD – While this isn’t a bottleneck on your CPU or GPU, getting an SSD will improve load times dramatically and ensure better in-game texture and asset loading.

,,,and that’s it!

If you have any lingering questions, leave a comment below and let us know. We hope this helped you!

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