You buy a brand new laptop with the latest processor and graphics card.
You set your laptop or PC up, plug it in and start playing the Shadow of the Tomb Raider or a demanding game.
Everything is going fine, settings are maxed out, the resolution is also maxed out and you are getting frame rates above 80+.
Suddenly, you notice that the frame rates drop sharply to 20 fps and stay there for a while until climbing back up to 80+ fps.
This keeps on repeating and it baffles you, because, with the components your machine has, you expect to get high fps no matter what.
What you just experienced was a CPU bottleneck.
What does bottleneck mean?
A CPU bottleneck happens when the CPU is not capable of keeping up with the GPU hence the drop in framerates.
You can experience slowdowns or stuttering spoiling your gaming experience. It is something like having water flowing from a pipe. You know the pipe is able to discharge 5 litres of water per second.
Related: CPU Throttling And How To Fix It
If you connect a hose to it that allows it to discharge water at 3 liters per second you are causing a bottleneck because you are limiting the amount of water it can maximally discharge.
An example is having a custom built PC having an 8th Gen Intel Core i3 and a GTX 1070. A CPU bottleneck will happen because the Intel Core i3 won’t be able to keep up with the processing speed of the GTX 1070. How does CPU bottleneck GPU.
In the video, notice how the game is stuttering? This is because the CPU usage is at 100% but the GPU is not.
This is a perfect example of a CPU bottleneck. The GPU has to “wait” for the CPU to process the data before it can send more. That is why the GPU usage rises and falls but the CPU is always at 100%.
What is a GPU bottleneck?
Just like there is a CPU bottleneck there is also a GPU bottleneck. A GPU bottleneck is vice versa of a CPU bottleneck.
A GPU that is incapable of keeping up with the processing speed of the CPU.
An example is having an Intel Core i7-8700K paired with a GT 1030 graphics card. The GT 1030 won’t be able to keep up because the i7 can process games much faster.
Other causes of CPU/GPU Bottleneck
Apart from the CPU/GPU components games also contribute to causing bottlenecks. Games are made different we have the CPU dependent games such as Resident Evil 7 and GPU dependent games like Crysis 3. CPU dependent games have high framerates on low settings.
GPU dependent show low frame rates on low settings if the GPU is not strong enough but if played on a more powerful GPU there’s considerable improvement in frame rates.
You can’t fix a bottleneck but only reduce its effects. You need to find the right components that will be able to optimize their performance very well. to play your type of games.
Going by this won’t fix or get rid or get rid of it but it will make sure the effects are greatly reduced.