AMD Threadripper Pro Review: An Upgrade Over Regular Threadripper?
by Dr. Ian Cutress on July 14, 2021 9:00 AM EST- Posted in
- CPUs
- AMD
- ThreadRipper
- Threadripper Pro
- 3995WX
CPU Tests: Rendering
Rendering tests, compared to others, are often a little more simple to digest and automate. All the tests put out some sort of score or time, usually in an obtainable way that makes it fairly easy to extract. These tests are some of the most strenuous in our list, due to the highly threaded nature of rendering and ray-tracing, and can draw a lot of power. If a system is not properly configured to deal with the thermal requirements of the processor, the rendering benchmarks is where it would show most easily as the frequency drops over a sustained period of time. Most benchmarks in this case are re-run several times, and the key to this is having an appropriate idle/wait time between benchmarks to allow for temperatures to normalize from the last test.
Blender 2.83 LTS: Link
One of the popular tools for rendering is Blender, with it being a public open source project that anyone in the animation industry can get involved in. This extends to conferences, use in films and VR, with a dedicated Blender Institute, and everything you might expect from a professional software package (except perhaps a professional grade support package). With it being open-source, studios can customize it in as many ways as they need to get the results they require. It ends up being a big optimization target for both Intel and AMD in this regard.
For benchmarking purposes, we fell back to one rendering a frame from a detailed project. Most reviews, as we have done in the past, focus on one of the classic Blender renders, known as BMW_27. It can take anywhere from a few minutes to almost an hour on a regular system. However now that Blender has moved onto a Long Term Support model (LTS) with the 2.83 release, we decided to go for something different.
We use this scene, called PartyTug at 6AM by Ian Hubert, which is the official image of Blender 2.83. It is 44.3 MB in size, and uses some of the more modern compute properties of Blender. As it is more complex than the BMW scene, but uses different aspects of the compute model, time to process is roughly similar to before. We loop the scene for at least 10 minutes, taking the average time of the completions taken. Blender offers a command-line tool for batch commands, and we redirect the output into a text file.
For Blender, we're seeing that SMT gives some extra performance in 64C mode, and comparing TR to TR Pro shows a big jump for the 3955WX over the 3960X despite having fewer cores, whereas the 32c TR is slightly faster than the 32c TR Pro. At 64c, there's little difference.
Corona 1.3: Link
Corona is billed as a popular high-performance photorealistic rendering engine for 3ds Max, with development for Cinema 4D support as well. In order to promote the software, the developers produced a downloadable benchmark on the 1.3 version of the software, with a ray-traced scene involving a military vehicle and a lot of foliage. The software does multiple passes, calculating the scene, geometry, preconditioning and rendering, with performance measured in the time to finish the benchmark (the official metric used on their website) or in rays per second (the metric we use to offer a more linear scale).
The standard benchmark provided by Corona is interface driven: the scene is calculated and displayed in front of the user, with the ability to upload the result to their online database. We got in contact with the developers, who provided us with a non-interface version that allowed for command-line entry and retrieval of the results very easily. We loop around the benchmark five times, waiting 60 seconds between each, and taking an overall average. The time to run this benchmark can be around 10 minutes on a Core i9, up to over an hour on a quad-core 2014 AMD processor or dual-core Pentium.
Corona is another bencmark where having SMT enabled does push the results higher, and there's no real difference between TR and TR Pro here.
Crysis CPU-Only Gameplay
One of the most oft used memes in computer gaming is ‘Can It Run Crysis?’. The original 2007 game, built in the Crytek engine by Crytek, was heralded as a computationally complex title for the hardware at the time and several years after, suggesting that a user needed graphics hardware from the future in order to run it. Fast forward over a decade, and the game runs fairly easily on modern GPUs.
But can we also apply the same concept to pure CPU rendering? Can a CPU, on its own, render Crysis? Since 64 core processors entered the market, one can dream. So we built a benchmark to see whether the hardware can.
For this test, we’re running Crysis’ own GPU benchmark, but in CPU render mode. This is a 2000 frame test, with medium and low settings.
Crysis CPU only has two main limitations: either 32 threads, or 23 cores. We typically run across 16 cores with all threads, and this benchmark tends to prefer cores with high IPC. The 3955WX seems to perform best here, although the Intel options come out ahead.
POV-Ray 3.7.1: Link
A long time benchmark staple, POV-Ray is another rendering program that is well known to load up every single thread in a system, regardless of cache and memory levels. After a long period of POV-Ray 3.7 being the latest official release, when AMD launched Ryzen the POV-Ray codebase suddenly saw a range of activity from both AMD and Intel, knowing that the software (with the built-in benchmark) would be an optimization tool for the hardware.
We had to stick a flag in the sand when it came to selecting the version that was fair to both AMD and Intel, and still relevant to end-users. Version 3.7.1 fixes a significant bug in the early 2017 code that was advised against in both Intel and AMD manuals regarding to write-after-read, leading to a nice performance boost.
The benchmark can take over 20 minutes on a slow system with few cores, or around a minute or two on a fast system, or seconds with a dual high-core count EPYC. Because POV-Ray draws a large amount of power and current, it is important to make sure the cooling is sufficient here and the system stays in its high-power state. Using a motherboard with a poor power-delivery and low airflow could create an issue that won’t be obvious in some CPU positioning if the power limit only causes a 100 MHz drop as it changes P-states.
POV-Ray seems to prefer the 64C/64T variants of Threadripper, but the difference between TR and TR Pro is ever so slightly in favor of the higher frequency TR processors.
V-Ray: Link
We have a couple of renderers and ray tracers in our suite already, however V-Ray’s benchmark came through for a requested benchmark enough for us to roll it into our suite. Built by ChaosGroup, V-Ray is a 3D rendering package compatible with a number of popular commercial imaging applications, such as 3ds Max, Maya, Undreal, Cinema 4D, and Blender.
We run the standard standalone benchmark application, but in an automated fashion to pull out the result in the form of kilosamples/second. We run the test six times and take an average of the valid results.
V-Ray shows benefit from having all 128 threads enabled, and it is interesting here that the performance difference between the 32c and 64c/64t options is next to zero. The W-3175X does well here by contrast, beating out the 32c variants.
Cinebench R20: Link
Another common stable of a benchmark suite is Cinebench. Based on Cinema4D, Cinebench is a purpose built benchmark machine that renders a scene with both single and multi-threaded options. The scene is identical in both cases. The R20 version means that it targets Cinema 4D R20, a slightly older version of the software which is currently on version R21. Cinebench R20 was launched given that the R15 version had been out a long time, and despite the difference between the benchmark and the latest version of the software on which it is based, Cinebench results are often quoted a lot in marketing materials.
Results for Cinebench R20 are not comparable to R15 or older, because both the scene being used is different, but also the updates in the code path. The results are output as a score from the software, which is directly proportional to the time taken. Using the benchmark flags for single CPU and multi-CPU workloads, we run the software from the command line which opens the test, runs it, and dumps the result into the console which is redirected to a text file. The test is repeated for a minimum of 10 minutes for both ST and MT, and then the runs averaged.
CBR20 scales up to 128 threads no problem, but we're seeing a preference in TR over TR Pro in this test where memory bandwidth doesn't matter much.
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Mikewind Dale - Wednesday, July 14, 2021 - link
I have a ThreadRipper Pro 3955WX, and I discovered something interesting about the memory bandwidth.Originally, I bought 4x64 GB ECC RDIMM because I thought 256 GB might be enough, and I wanted to leave some empty RAM slots to populate with 128 GB RDIMMs if those ever became cost-effective. (Right now, 128 GB RDIMMs are about triple the price of 64 GB.)
CPU-Z and AIDA64 reported "quad" channel memory, and AIDA64's memory benchmarks showed reasonable memory performance.
But I discovered that 256 GB wasn't enough for my application, so I bought 2 more 64 GB RDIMMs.
At this point, I had 6 DIMMs populated. CPU-Z and AIDA64 both reported "hexa" channel memory, but AIDA64's memory benchmarks showed that my memory performance was about 2/3 that of a Ryzen.
So I bought 2 more RDIMMs again, for a total of 8. Now, my memory benchmark in AIDA64 is much closer to expected.
So the moral of the story is: you can populate 4 DIMMs, or you can populate 8, but don't dare populate 6. Populating precisely 6 DIMMs will absolutely cripple your memory performance, whereas 4 DIMMs still have acceptable performance.
kobblestown - Wednesday, July 14, 2021 - link
The 3955 probably has only 2 CCDs and is therefore limited to 4 DDR channels throughput. It seems that each IF link has the throughput of 2 DDR channels and this makes sense.You should keep in mind that the IO die has in effect 4 dual channel controllers and you may have populated them suboptimally. If you have two dual channel controllers fully populated and two half populated (instead of a third fully populated and the fourth one staying empty) you'll have skewed results. Also, there was some noise about Milan working better with 6 channel configurations so it may be something specific to Rome chips.
Rudde - Wednesday, July 14, 2021 - link
Server providers had requested for 6 channel memory support for server processors and that was implemented in Milan.McFig - Wednesday, July 14, 2021 - link
What kobblestown is suggesting is that maybe Mikewind Dale could have gotten the 6 RDIMMs working by moving one of them so that each pair is fully populated.Mikewind Dale - Wednesday, July 14, 2021 - link
McFig, there are only 8 slots, so I'm not sure how I could have moved the 6 DIMMs among the 8 slots to ensure that each pair is populated.1_rick - Wednesday, July 14, 2021 - link
He probably means "each of 3 pairs fully populated".DougMcC - Wednesday, July 14, 2021 - link
I think the question is whether 3/3 is better than 4/2kobblestown - Friday, July 16, 2021 - link
Heya! Sorry for the nebulous formulation. In terms of the number of DIMMS per memory controller, I suggest having 2+2+2+0 instead of 2+1+2+1. One needs to figure out what this means for any particular MB. But as DougMcC suggests, that would probably mean having 4 DIMMs on one side of the CPU and 2 on the other, rather than having 3 DIMMs on each side. The latter is bound to be suboptimal. Whether the former offers an improvement is something that I would be very interested to know but could be that Rome has some shortcoming in this area which is addressed in Milan.Again, dual CCD configurations are limited to 4 channel bandwidth but it's still worth it to have all channels populated so you don't get bitten by badly handled assymetry and the IO does not fight (too much) with the cores for the bandwidth.
kobblestown - Friday, July 16, 2021 - link
BTW, one should also check the memory interleaving options in the UEFI. Maybe the way the IO die aggregates the memory channels can be tweaked to achive the expected performance even with 6 DIMMs. Or maybe that's only achievable with Milan.Mikewind Dale - Friday, July 16, 2021 - link
Ahhh, I see what you mean. Thanks. Well, I have 8 DIMMs now, and I don't want to mess with my system any more. Maybe Anandtech can test this.