CPU Rendering

What is CPU Rendering?

CPU rendering refers to the process of representing images by using only the CPU. It is not dependent on the performance of the graphics card installed or its number or Video RAM.

Understanding CPU Rendering

What is CPU Rendering

CPU rendering, just as the name suggests, is a process of producing images by processing data by making the best use of the higher clock speeds of the cores of the processors instead of the GPUs.

It is the architectural designs of these CPUs that provide a significant edge while creating a scene which consists of several tiny details, complex geometries, and a large number of calculations.

Though it may take longer to process all the relevant data by a CPU in comparison to a GPU, the end result will be more accurate and high quality images.

That is why CPU rendering is more favored than GPU rendering for making animated movies, complex computer graphics production and others.

In fact, CPU rendering has become an integral part of 3D rendering which will ensure that every image along with every minute detail in it conforms to the actual 3D scene.

This will make the images look more real-life-like.

Ideally, in 3D rendering, the principles followed may vary depending on the different types of rendering software used.

However, the basic principle always remains the same, which is what the CPU makes the best use of.

It is to calculate the parameters that are set in the model depending on the particular method of calculation that is laid down by the rendering software. These parameters include:

All these when done properly will ensure that the digital model is changed into a real visualization.

It is only after that the graphics card will display the image on the computer screen.

This means a lot of calculations and therefore a powerful processor is required in order to solve a lot of problems while rendering with accurate calculations.

For example, consider an image of an apple being illuminated by a beam of light.

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In this particular case, in order to render the perfect image, different calculations are required to be made to determine different aspects of the image produced such as:

This translates to a lot of complex calculations and it is the CPU that can resolve these issues with the high frequency of the cores in it. and, higher the number of cores, the better and faster will be the rendering.

Ideally, the conventional CPU arithmetic rendering software uses the CPU for rendering.

This is because the rendering software can support the multi-threading ability of the CPUs very well.

The rendering speed will be even doubled when the cache is doubled and the frequency is left the same.

With all these features, using CPU rendering software will offer a very strong guarantee for improved work efficiency, high quality images and more accuracy.

If you want faster results, you can use a CPU farm easily to get a month-long project rendered in as little as five minutes!

Why Does Rendering Use CPU?

In simple terms, rendering uses CPU for enhanced graphic fidelity.

Typically, graphics rendering is a process that takes time for completion if quality is the priority.

You simply cannot rush things or else the quality of the image will be compromised.

This is what the GPUs do.

The thousands of cores in the GPUs rush things and the end result is an image that is often grainier or blurrier.

That is not the case if rendering uses CPU.

The images can be delivered after a long time but it will surely be devoid of any noise and will be of exceptionally high quality with all minute details portrayed in it.

If a CPU comes with a larger number of cores and higher core clocks, it will also improve the rendering speed.

Therefore, using CPU for rendering is the most feasible option to have a higher price-performance ratio.

The CPU, as you may know already, is the ‘brain’ of a computer.

This particular component handles the bulk of the calculations which involves all types of computation jobs including rendering.

While rendering, the CPU traces the rays of light that bounce in a scene and there are millions of such rays that need to be calculated in order to get the accurate picture out of the rendering engine.

For this, a lot of separate frames are required to be rendered during the entire project such as making a film or a video.

This is where the multi-core processors come into play since they can handle the calculation of each of the rays separately when they interact with the light sources and the objects.

This makes it one of the best workflows.

If there is an absence of such interdependence between the calculations of each ray, the perfect picture cannot be portrayed.

These types of calculations can also be handled by the GPUs or the Graphics Processing Units pretty well but the processors in the GPUs or video cards can only handle a number of small calculations at a given point of time.

It is for this reason there has been a notable increase seen in the last decade regarding GPU-based rendering.

However, in those specific cases the CPU matters the most.

This is because the higher clock speed of the CPUs is far more important than the large number of core counts of the GPUs when it comes to feeding data simply to the video cards.

The CPU also plays a significant role in the operation of the video cards based on the number of Peripheral Component Interconnect Express or PCI Express lanes that are supported by the system.

Typically, there are different aspects of the CPU that will have a significant impact on the rendering speed and the real world performance in addition to the two chief attributes namely the core count and the clock speed.

These aspects are:

All these can make a huge difference in the performance of the CPU while rendering.

That is why it is more important to test the CPUs based on varied data sets and real-world applications rather than simply on their specs in order to determine their actual performance levels.

Is the CPU Good for Rendering?

The short and simple answer to this question is: yes, it is.

If you have a powerful CPU installed in your computer with a large number of cores, such as the Threadripper 3990x, which comes with as many as 64 cores in comparison to 4 to 8 cores in any average CPUs, you can have an outstanding rendering experience.

Yes, it is true that the number of cores in a CPU is far too less in comparison to the number of cores in a GPU which often adds up to thousands, but that does not mean CPU rendering is inferior to GPU rendering.

It is all about the clock frequency which is much higher in the case of the cores of a CPU than the cores in a GPU.

Higher clock frequencies enable the cores to execute the instructions and complete a given task much faster.

And for rendering, this is crucial and therefore it is good to go for CPU rendering.

Moreover, there are lots of advantages of CPU rendering, which is another aspect that makes it so good and a feasible option to choose.

Here are some other good reasons why most users, especially the professionals, prefer using a CPU render engine over a GPU.

The CPU render engines will allow the users to deal with complex or intricate projects with ease, especially those that involve a large number of varied computing operations.

The CPUs can handle these operations very smoothly in comparison to a GPU which is designed to process large amounts of data in the same way over and over again.

Therefore, CPU rendering is good if you want different operations to be executed.

The CPU render engines can also handle different types of work smoothly due to the large amount of memory.

Usually, a CPU system can support a memory of up to 768 GB in each CPU which means that a 4x CPU system can have as much as 1.5 TB of memory or more.

On the other hand, the higher memory amount of a GPU may be up to 80 GB and it will not stack up if you add more GPU renderers.

On the contrary, it may simply hinder the performance of the existing render engine.

Stability in performance is another aspect that makes CPU rendering so good.

Typically, the CPU renderers are built into the system which allows it to be totally integrated with the atmosphere of your computer.

This offers increased reliability and stability which eventually results in a seamless rendering and higher user experience.

On the other hand, the GPU renderer is typically an external component and therefore, more often than not, these cannot be integrated properly.

Add to that, regular driver updates may also hinder it at work apart from a high chance of the system crashing eventually.

And, quality of the image is perhaps the most significant reason to go for CPU rendering.

This is even more important than the speed of processing the media, especially to the professionals and those who are looking for nothing but the best images.

Once again, it is all due to the fact that it is an integrated solution.

Therefore, if you use your computer for graphics design tasks especially, make sure that you invest as much money as you can afford in the CPU.

Since a CPU is exceptionally sensitive to the amount of cores, choose a multi-core processor for the best results and exceptional performance improvements. If the number of cores is higher it is even better.

Also, apart from that, focus on the response speed of the hard disk and memory which should be quite high as well.

Therefore, in order to enjoy the benefits offered by CPU rendering, all you have to do is choose the right kind of CPU for your computer system. Research is the key in that case to find the best CPU with a high rendering performance.

And, of course, comparing several benchmarks is also very important.


Coming to the end of the article, it can be said that CPU rendering is very important for those who prefer accuracy and rendering quality over time efficiency.

You will be benefited a lot if you choose CPU rendering especially if you are a professional.