Why Does CPU Bottleneck At 1080P?

A bottleneck is a limitation within a system caused by another component. Bottlenecks are normal, but they can be detrimental to performance in certain situations.

In games, a bottleneck manifests in the form of lower frame rates, this can be observed as a sudden frame rate drop, and it’s usually caused by the CPU bottlenecking the GPU.

In simple terms, the CPUs job is to process data and keep up with the GPU in games. At 1080P, the GPU will be processing a lot more frames than 1440P or 4K which will cause the CPU to fall behind the GPU.

Why Does The CPU Bottleneck At 1080P?

It’s not just 1080P, the lower the resolution, the higher the CPU load will be, so 720P would be more of a bottleneck than 1080P.

Anyways, the reason why 1080P bottlenecks more than 1440P or 4K has to do with the CPU/GPU relationship, and how frames are processed.

The more FPS you get, the more load your computer puts on the CPU, since 1080P is relatively easy to run by today’s standard, it will be more CPU bound.

4K is hard for most GPUs to run, so the CPU has to wait more on the graphics card to process each frame hence it being less CPU intensive.

How Can I Reduce Bottlenecks At 1080P? (Reducing CPU Load)

If you’re looking to stick with 1080P, but you want to reduce the bottleneck, there’s a few things you can do to help.

The goal when reducing a bottleneck is to get as much performance out of the system, and to do this is to reduce the load percentage on the CPU.

Buying A New CPU/Processor


Purchasing a new and better CPU would be the obvious way to reduce a bottleneck, focus more on single-core performance such as clock speeds.

Games prefer single-core performance over multicore performance, so core count isn’t as important, but we recommend going for at least 6 cores.

The recommended clock speed for when buying a new CPU is 4-5GHz, and if possible, go for the latest generation of whatever brand you’re going for.

So, if you’re going for Intel, go for the latest iteration of their Core processors, and for Ryzen, go for the latest Ryzen generation.

This ensures you get as much performance out of each clock speed “maximizing IPC potential”, because newer processors possess IPC improvements compared to their predecessors which contribute to single-core performance.

To put this into perspective, the Intel 13th generation processors will outperform their 12th generation counterparts due to IPC improvements.

Also Read: What Is Single Core Performance?

Watch Out For CPU Cache

3D V-cache

The CPU cache is having an increasingly prominent effect on games, with more CPU cache more specifically “L3 cache”, the better the CPU is at certain games.

With the Ryzen, they’re introducing a new method of stacking cache on the CPU die, it’s called “3D V-Cache”, and the first example is on the Ryzen 7 5800X3D.

The Ryzen 7 5800X3D is able to compete with CPUs such as the Intel I9 12900K despite the 5800X3D having worse single-core performance.

The logic behind having more cache on the CPU die is that the CPU will rely less on the main system memory(RAM).

So the CPU spends a lot less time waiting and processing simple instructions which will significantly speed up the efficiency of your system.

Overclocking Your CPU

If buying a new CPU isn’t an option, you can try overclocking your existing CPU, this is a free and effective method to get the most out of your computer.

Overclocking focuses on increasing the core clock speed of your processor, this effectively increases the single-core performance which in turn gives more frame rates in games.

CPU overclocking is usually done through the BIOS, and it involves manually increasing the clock speed modifier to something higher.

But it isn’t as simple as increasing the clock speed modifier to the highest value, this will always result in failure, you need to follow rules when overclocking.

Tips For When You Want To Overclock Your CPU:

  • Increase the clock speed modifier in small increments
  • Only increase the voltage when your system crashes and you really want more performance
  • Always ensure you have sufficient cooling
  • Test the system, and ensure everything is running stable

Buying More And Faster RAM


Your RAM has an impact on the performance of your CPU, this is usually caused when the RAM is bottlenecking the CPU.

If the RAM is bottlenecking the CPU, then this means the CPU will slow down which in turn means it will have a harder time processing frames at 1080P.

The RAM can bottleneck the CPU in 2 ways, either the RAM capacity is too low, or the RAM is too slow.

In this scenario, we recommend picking up XMP RAM as it can be pretty fast, and for games, we recommend going for at least 16GB of RAM.

Some games may require at least 32GB of RAM, but those types of games are usually simulations or heavily modded instances of games.

Also Read: Can RAM Bottleneck CPU?

Overclocking RAM

If buying more RAM is not an option, then overclocking the RAM will improve performance just like overclocking the CPU will.

Ideally, you will want your RAM to run at high frequencies with low timings, this is the optimal setup which should allow the CPU to process instructions effectively.

If you have XMP RAM, then overclocking the RAM should be fairly simple, it usually involves pressing one button the BIOS, and it will apply values that were set by the RAM manufacturer.

However if you do not have XMP RAM, then you will have to manually overclock your RAM. Fundamentally, it’s pretty simple.

How To Overclock Your RAM Manually:

  • Navigate to the memory tweaking settings in your BIOS
  • Locate the “DRAM Frequency” setting
  • Begin to slowly increase the RAM frequency, the lower the value, the better.
  • You also may want to increase the voltages in small increments to keep everything stable
  • Work on optimizing the RAM timings (lower is better)
  • Restart the PC

After overclocking the RAM, you should see a noticeable difference in the frame rates, the CPU should be able to operate more efficiently due to waiting less for instructions.

Overclocking the RAM may have a positive effect whilst gaming at 1080P.

Also Read: How Much Does RAM Speed Affect FPS?


In conclusion, the CPU becomes a limiting factor the lower the resolution is, so when you game at 1080P, the CPU will run at a higher load, typically closer to 100%.

Ideally, you will want your CPU to have lower usage whilst gaming as this implies that it’s less of a bottleneck on the GPU

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