KeyShot 7 CPU Comparison: Skylake-X vs Threadripper

Introduction

KeyShot is widely used for creating 3D visuals and animations. When rendering those graphics, the performance of the central processor (CPU) in a computer is of paramount importance. CPU-based rendering generally scales well with both clock speed and core count, but those specifications cannot be directly compared across different brand or generations of processor. Here at Puget Systems we do real-world testing to ensure we provide our customers with the right computer for their needs.

In this article we are going to look at the latest CPU options from Intel and AMD, both of which have recently released high core count processors that should be great for KeyShot. From Intel we have the Core X series of processors, which were code-named Skylake X. They come in 6- to 12-core models currently, though up to 18-core variants will be coming in the future. Up against these chips are AMD's new Threadripper processors, based on a pair of Zen chips combined into a single package. We'll be looking at the 12- and 16-core models in that family to see how they stack up against Intel's traditional lead in this application.

We are also including several other CPU platforms in this article, as points of comparison. We've got Intel's lower core count Kaby Lake chips, along with AMD's similar Ryzen line. Intel's Xeon versions of the Skylake X are also present, called Skylake W or Xeon W depending on where you look. And to top things off, a dual Xeon configuration is included as well – to show what can happen if you put two powerful processors together.

Test Setup

To see how these different CPUs perform in KeyShot 7, we ran the time-limited trial version on the following configurations:

These test configurations include a wide range of Intel and AMD processors. CPU-based rendering in KeyShot is known to scale well across multiple cores, so the lower core count processors are mostly here for reference. Such 4, 6, and even 8 core chips are common on home and gaming computers, as well as office workstations, but they don't really hold up well under heavily threaded applications like rendering. Ideal performance for rendering will be found with 10+ cores, and a while the focus of this particular article is on single-CPU performance we included a dual Xeon processor setup as an example of how well such a system does with heavily threaded workloads.

The results presented below are from KeyShot 7, the current version as of this writing. It is available for a short, fully-functional trial – and while there is no dedicated benchmark mode, several test files are included. We used two of these: the "camera benchmark" to measure FPS (frames per second) while viewing real-time performance in the viewport ;and the cube-like "animation" file to test rendering several images in sequence for a video. We also tested a third file from the KeyShot website, "Bathroom Interior", to check multi-pass rendering on a still image. The results from each of these three tests are broken down and discussed in the next section.

It is also worth noting that there are some differences in the amount and speed of RAM across the various test platforms, as well as the video card utilized. We prefer to use the speed of memory that each CPU is rated for, according to its manufacturer, but in the case of the new Xeon W processors we couldn't get the rated speed running on the motherboard sample we have. Intel processors generally show little impact from small changes in memory speed, though, so that shouldn't impact the results much. Likewise, since this benchmark focuses on the CPU, the difference between the two video cards used will not affect the results.

Benchmark Results

Here are the results for the various CPUs and files we tested in KeyShot 7:

What is tested here is the frames per second (FPS) of the continuous render mode available in KeyShot's viewport. Using the included "camera benchmark" file is recommended on the KeyShot forum as a way to measure system performance. Higher numbers are better.

This second test measures the time taken to render a single image with higher quality (128 passes). Shorter times = faster performance.

Since rendering in KeyShot is a heavily threaded application, there is a clear spread between the different processors based on core count. The dual Xeon, with a total of 28 cores, definitely wins out – but that is a much more expensive system and is really just included here as a point of reference. Among the single CPU workstations, AMD's 16-core 1950X is neck-and-neck with Intel's 12-core i9 7920X, though AMD's processor costs a bit less and is a hair faster. Next up are AMD's 12-core 1920X against Intel's 10-core i9 7900X and W-2155, with the Intel processors winning this matchup but again costing more. The rest of the processors fan out from there in accordance with the number of cores they have.

Our final KeyShot test looks at the time taken to render over a hundred images of a cube revolving and moving into a single video clip. The results here appear to be a little less spread out, likely meaning that more of the overall workflow is single-threaded, but AMD's Threadripper processors win out against Intel's Skylake X chips again.

An interesting thing to note here is that Intel's Core X and Xeon W lines match up very closely on a per-core basis. That makes sense as these are based on the same Skylake technology under the hood, but Intel charges a lot more for the Xeon variants since they support features like ECC memory. If that matters to you then they are a viable option in terms of performance, but be aware that you will pay a premium for them. Many AMD processors also support ECC (though not registered) memory, but not all motherboards do.

It is also worth noting that Intel has 14, 16, and even 18-core models coming soon in the Core X series. When they are released later this year some of them will likely beat out AMD's Threadripper chips for the top performance spot in single CPU rendering, but at a higher price tag. AMD and Intel both have server-class processors with even more cores as well: up to 32 on AMD's EPYC and up to 28 from Intel's Xeon Platinum line. With their focus on the multi-CPU server segment those may not come into play here, but if a manufacturer puts out a single-socket workstation motherboard that is compatible with either of those platforms then they may be worth a look.

Conclusion

Here is a summary of KeyShot 7 performance between just the top two Skylake X and Threadripper processors:

Based on these test results, and as of the writing of this article, Threadripper is clearly in the lead for CPU based rendering in KeyShot. The 16-core 1950X not only beats the 12-core i9 7920X, it also costs less. Looking to the near future, Intel's 14-18 core processors are likely to take back the performance lead – but will still cost more than AMD's offerings. We will test those when they become available and publish additional results at that time. We will also use this data to craft our recommended systems for KeyShot going forward.

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