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OctaneRender GPU Platform Comparison: Skylake X, Xeon W, and Threadripper

Written on September 6, 2017 by William George
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Introduction

OctaneRender, from OTOY, is a real-time, physically correct 3D rendering engine that uses GPUs (video cards) instead of CPUs for processing. This is a relatively new approach, as traditional graphics rendering was done on CPUs instead. Graphics processors are ideal for highly parallel tasks like rendering, though, and it is easier to fit multiple GPUs in a single computer than multiple CPUs.

However, care does have to be taken when putting more than one video card into a workstation: there needs to be space in the chassis, the right type of PCI-Express slots in the correct layout on the motherboard, a large enough power supply, and plenty of cooling. In this article we are going to look at several platforms - motherboard chipsets along with a matching CPU - to see how well they handle the scaling of performance in OctaneRender.

Test Setup

To see how the different platforms scale in OctaneRender, we used the following configurations:

Test Platforms

Platform:

Intel X299 Chipset / Skylake X Intel C422 Chipset / Skylake W AMD X399 Chipset / Threadripper

Motherboard:

Gigabyte X299 AORUS Gaming 7 (rev 1.0) Gigabyte MW51-HP0 Gigabyte X399 AORUS Gaming 7
(rev 1.0)
CPU:

Intel Core i7 7820X 3.6GHz
(4.3/4.5GHz Turbo) 8 Core

Intel Xeon W-1255 3.3GHz
(4.5GHz Turbo) 10 Core

AMD Threadripper 1950X 3.4GHz
(4.0GHz Turbo) 16 Core
RAM: 8x Crucial DDR4-2666 16GB
(128GB Total)
4x DDR4-2133 16GB ECC Reg. (64GB total) 8x Crucial DDR4-2666 16GB
(128GB Total)
GPU: 1-4x NVIDIA GeForce GTX 1080 Ti 11GB
Hard Drive: Samsung 960 Pro M.2 PCI-E x4 NVMe SSD
OS: Windows 10 Pro 64-bit
Software: OctaneBench 3.06.2

These test configurations cover six major CPU platforms that are currently available, four from Intel and two from AMD. With the tested motherboards they support either 2, 3, or 4 GPUs at maximum - with a mix of x8 and x16 PCI-Express lanes per card, depending on the board and card layout. In our past testing with Octane we found that cards running with x8 vs x16 lanes made no substantial difference.

For the video cards themselves we used NVIDIA's GeForce GTX 1080 Ti, a well-respected GPU for this application due to its high speed and fairly large RAM capacity with a reasonable price tag. Multiple cards were run on each platform, up to 2-4 depending on the board.

To determine performance, we ran OctaneBench 3.06.2 and recorded the results from each hardware combination. That test splits results into several sections, but rather than overwhelm readers with every number we opted to just report to the total scores. They are found in the chart below, separated by platform and the number of GPUs - which are color coded for easy cross-platform comparisons.

Benchmark Results

Here are the total scores from OctaneBench for the platforms and number of GPUs we tested:

OctaneBench 3.06.2 Multi-GPU Platform Performance Comparison

The main takeaway here is that the platform does not make a huge impact on performance. There are a lot of little variances, a few percentage points up or down, that are within margin of error. A couple of the larger differences are worth mentioning:

  • Intel's Z270 / Kaby Lake platform has the lowest single-GPU score, about 10% lower than the average here. Its dual GPU score is also on the lower side, though not by as wide a margin. This could be an indicator for the smaller core count being a bottleneck, but it is hard to say for sure.
  • Intel's new X299 / Skylake X platform is coming in below average on all three tests (1 - 3 GPUs). This may well be due to growing pains in its architecture and BIOS / driver support, or due to the specific CPU used in testing. It only supports 28 PCI-E lanes, which means that with more than one GPU each is running at x8 speed... but that doesn't account for the slightly low single GPU score, and in our past testing with Octane we found that x16 vs x8 lanes made no substantial difference. We may dig further into this in a future article.

Conclusion

Based on our test results, the platform itself isn't a huge concern for Octane. All the major chipsets of today perform within a few percentage points of each other, with possible exception of X299 - which is still going through teething, and may well end up matching the rest in the end.

What does matter, though, is your budget and how many GPUs you want to use. If you are just going for one or two GPUs, even Intel's mainstream Z270 chipset will work - though you get a little bit of a boost with a higher-end platform, along with support for higher core count processors and more RAM. For three or four GPUs, you need a configuration with enough PCI-Express slots and lanes to support all of the cards. That limits the options somewhat, but both AMD's X399 / Threadripper and Intel's C422 / Xeon W are quite strong in that regard. Even the aging X99 platform does quite well here, and it has a solid track record of dependability.

As of this writing, no X299 motherboards are available yet which support more than three GPUs - but when they do come we will test them and publish updated results. If there are other platforms you would like to see tested, let us know in the comments!

Recommended Systems for OctaneRender

Tags: GPU, Rendering, Octane, Render, OTOY, OctaneBench, Benchmark, Chipset, Motherboard, Performance, Intel, AMD, Core, i7, i9, Skylake X, Xeon W, Ryzen, Threadripper, X99, X299, C422, X399, Z270, X370, Video, Card

Good read. "highly parallely"

Posted on 2017-09-14 05:26:12

Oops, good catch on that typo! It has been corrected :)

Posted on 2017-09-14 15:56:55
Niko Nikolov

Can the xeon w be used on normal gaming x299 motherboards?They are the same socket and we did see this with x99 and xeon e5.
Cheers

Posted on 2018-01-06 00:51:13

My understanding is that with the Skylake-X / -W generation of chips they can no longer be used across chipsets (like past generations could). However, I have not physically tested that myself... maybe I'll give it a try at some point, and if it turns out you can I will post another reply here :)

Posted on 2018-01-08 21:25:10
Niko Nikolov

Thank you.I on the other hand will speak with Asrock as they do tend to give xeons support and if i learn something will notify here too.
Cheers

Posted on 2018-01-09 12:14:07

No, you cannot do that anymore. Xeon W requires a C422 chipset while the Core i7/i9 CPUs require X299. They are physically the same socket, but the BIOS/Firmware is not cross-compatible. If you try to put one into the opposite's chipset, the system simply won't POST.

Posted on 2018-01-08 21:28:09
☠☠☠

Is your C422 motherboard a pre-release sample, and is your W-2155 Xeon W an engineering sample? I thought that both the C422 motherboards and Xeon W chips will not be available for retail purchase until December?? Can you please run some performance benchmarks using Adobe software to compare the 10-core W-2155 to the other Skylake-X CPUs that Matt Bach ran on Sep 25? I am HIGHLY curious to see how the W-2155 compares to the 10-core i9-7900X when using Premiere Pro CC, After Effects CC, Lightroom, and Photoshop, along with the other HCC i9 CPUs that Matt Bach posted on Monday. THANKS!!

Posted on 2017-09-30 22:20:08

Most of the CPUs we test with are samples from manufacturers, rather than retail purchased, including these Xeon W models. We have not found that there is normally a difference in performance between samples and retail boxed / tray CPUs, though.

As for the motherboard, we had an early sample originally and then if memory serves Gigabyte sent us a second one after that. I cannot recall which I was using for this set of testing.

I included the Xeon W line in some other tests recently as well, though not Adobe products (that is Matt's area of expertise). In CPU-based applications, though, the Xeons performed more or less in line with the Core X series processors that have the same core counts. Sometimes the Xeons were a little ahead or behind, but given their much higher cost we have decided (so far, at least) not to carry them this time around. You can get Core X processors from 6 to 18 cores, so unless you absolutely need official ECC memory support then there is little point to using them (in my opinion). And if you do want to go the Xeon route, it will cost many hundreds of dollars more for similar performance.

Posted on 2017-10-02 17:44:52
Mark Johnstone

"You can get Core X processors from 6 to 18 cores, so unless you
absolutely need official ECC memory support then there is little point
to using them (in my opinion)."

It seems like you might be missing two useful configurations of Xeon-W processors: Xeon W-2125 (4 cores for $444) and Xeon W-2135 (6 cores for $835). Both of those processors have 48 PCI lanes, and can be used in a motherboard for 4 GPU compute/rendering. The least expensive other Intel chip with close to that many PCI lanes is the Core i9-7900x with 44 lanes (10 cores for $1000). The AMD Threadripper processors have plenty of PCI lanes, but they are slower if you also have an application that heavily depends on single-threaded performance. The Xeon-W processors all also have 2 AVX-512 FMA units, which *might* become important in the future (if more software is written to take advantage of them).

If you need fast single-thread performance, and 4 GPUs, the least expensive option seems to be these two Xeon-W processors. The fact that ECC is thrown in is just a bonus.

Am I missing something?

Posted on 2017-10-10 01:21:45

I suppose if you very specifically need 4 GPUs, single-threaded performance, and do *not* need / care about multi-threaded performance... then maybe one of those would make sense. Once you are spending that much, though, I'd personally prefer to get the i7 7900X (less than $200 more than the 6-core Xeon you mentioned) since it has 66% more cores while keeping a high clock speed. Right now, X299 motherboards aren't yet available with support for four GPUs - but that should be coming soon, and the 44 lanes on that CPU is plenty for running four cards at x8 each... or even one at x16, and the other three at x8.

Or if you value multi-threaded performance as much as single-threaded, the Threadripper chips from AMD really do shine at their price points.

I really wish Intel didn't overcharge quite so much for their single-socket Xeons, as they are good processors... just really costly for what you get.

Posted on 2017-10-10 04:16:57
Ryan P

ROG RAMPAGE VI EXTREME/ROG RAMPAGE VI APEX are available and should be able to support four GPUs on the x299 platform. Why aren't they used for testing?

Posted on 2017-10-10 16:29:34

Ah, it is good to see that some quad GPU boards are starting to come out for X299! Those were not yet available when we did our testing in the weeks leading up to the Skylake-X launch. I will see if we can get one of those in for testing, though hopefully Asus (or another manufacturer) will put out a more workstation-oriented motherboard with similar PCI-E slot layout. Something more like the X99-E WS would be more appealing to us as a product to actually carry.

Thank you for pointing that out, Ryan :)

Posted on 2017-10-10 16:44:27
Ryan P

No prob - agree they need to drop a WS specific model though... although would be interested to see one of the Rampage ones with an i9 chip tested if you get a chance. I'm tempted to stick with building an x99 machine for now... seems like everything coming out at the moment is pure marketing BS. Threadrippers look nice but wish they had an option that was a bit faster for single thread activity.

Posted on 2017-10-11 18:27:21
Mark Johnstone

Have you been able to get hold of one of the new Asus x299 sage WorkStation motherboards? Do you have any idea when they might be available?

Posted on 2017-11-28 18:52:10

No, they don't seem to be available yet - but it is on our radar to get hold of one and test it out as soon as we can :)

Posted on 2017-11-28 20:53:20
Mark Johnstone

Now that the Asus x299 sage WorkStation motherboards are starting to appear at retail, have you been able to get hold of one for testing? There have been *very few* reviews (I found 1).

Posted on 2018-03-06 01:53:21

We have not, and honestly at this point - with how long that board had been MIA - we have begun down the path of just carrying Xeon W in order to get both increased RAM capacity and quad GPU. An Intel C422 based board, similar to the one used in the testing above, is in qualification here now.

Posted on 2018-03-06 16:43:23