The AMD Threadripper 2990WX 32-Core and 2950X 16-Core Review
by Dr. Ian Cutress on August 13, 2018 9:00 AM ESTConclusions: Not All Cores Are Made Equal
Designing a processor is often a finely tuned craft. To get performance, the architect needs to balance compute with throughput and at all times have sufficient data in place to feed the beast. If the beast is left idle, it sits there and consumes power, while not doing any work. Getting the right combination of resources is a complex task, and the reason why top CPU companies hire thousands of engineers to get it to work right. As long as the top of the design is in place, the rest should follow.
Sometimes, more esoteric products fall out of the stack. The new generation of AMD Ryzen Threadripper processors are just that – a little esoteric. The direct replacements for the previous generation units, replacing like for like but with better latency and more frequency, are a known component at this point and we get the expected uplift. It is just this extra enabled silicon in the 2990WX, without direct access to memory, is throwing a spanner in the works.
2950X (left) and 2990WX (right)
When some cores are directly connected to memory, such as the 2950X, all of the cores are considered equal enough that distributing a workload is a fairly easy task. With the new processors, we have the situation on the right, where only some cores are directly attached to memory, and others are not. In order to go from one of these cores to main memory, it requires an extra hop, which adds latency. When all the cores are requesting access, this causes congestion.
In order to take the full advantage of this setup, the workload has to be memory light. In workloads such as particle movement, ray-tracing, scene rendering, and decompression, having all 32-cores shine a light means that we set new records in these benchmarks.
In true Janus style, for other workloads that are historically scale with cores, such as physics, transcoding, and compression, the bi-modal core caused significant performance regression. Ultimately, there seems to be almost no middle ground here – either the workload scales well, or it sits towards the back of our high-end testing pack.
Part of the problem relates to how power is distributed with these big core designs. As shown on page four, the more chiplets that are in play, or the bigger the mesh, the more power gets diverted from the cores to the internal networking, such as the uncore or Infinity Fabric. Comparing the one IF link in the 2950X to the six links in 2990WX, we saw the IF consuming 60-73% of the chip power total at small workloads, and 25-40% at high levels.
In essence, at full load, a chip like the 2990WX is only using 60% of its power budget for CPU frequency. In our EPYC 7601, because of the additional memory links, the cores were only consuming 50% of the power budget at load. Rest assured, once AMD and Intel have finished fighting over cores, the next target on their list will be this interconnect.
But the knock on effect of not using all the power for the cores, as well as having a bi-modal operation of cores, is that some workloads will not scale: or in some cases regress.
The Big Cheese: AMD’s 32-Core Behemoth
There is no doubting that when the AMD Ryzen Threadripper 2990WX gets a change to work its legs, it will do so with gusto. We were able to overclock the system to 4.0 GHz on all cores by simply changing the BIOS settings, although AMD also supports features like Precision Boost Overdrive in Windows to get more out of the chip. That being said, the power consumption when using half of the cores at 4.0 GHz pushes up to 260W, leaving a full loaded CPU nudging 450-500W and spiking at over 600W. Users will need to make sure that their motherboard and power supply are up to the task.
This is the point where I mention if we would recommend AMD’s new launches. The 2950X slots right in to where the 1950X used to be, and at a lower price point, and we are very comfortable with that. However the 2950X already sits as a niche proposition for high performance – the 2990WX takes that ball and runs with it, making it a niche of a niche. To be honest, it doesn’t offer enough cases where performance excels as one would expect – it makes perfect sense for a narrow set of workloads where it toasts the competition. It even outperforms almost all the other processors in our compile test. However there is one processor that did beat it: the 2950X.
For most users, the 2950X is enough. For the select few, the 2990WX will be out of this world.
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Eastman - Tuesday, August 14, 2018 - link
Just a comment regarding studios and game developers. I work in the industry and 90% of these facilities do run with Xeon workstations and ECC memory. Either custom built or purchased from the likes of Dell or HP. So yes, there is a market place for workstations. No serious pro would do work on a mobile tablet or phone where there is a huge market growth. There is definitely a place for a single 32 core CPUs. But among say 100 workstations there might be a place for only 4-5 of the 2990WX. Those would serve particles/fluids dynamics simulation. Most of the workload would be sent to render farms sometimes offsite. Those render farms could use Epyc/Xeon chips. If I was a head of technology, I would seriously consider these CPUs for my artists workflow.ATC9001 - Wednesday, August 15, 2018 - link
Another big thing which people don't consider is...the true "price" of these systems is nearly neck and neck. Sure you can save a couple hundred with AMD CPU, but by the time you add in RAM, mobo, PSU, storage etc....you're talking a 5k+...Intel doesn't want AMD to go away (think anti-trust) but they are definitely stepping up efforts which is great for consumers!
LsRamAir - Thursday, August 16, 2018 - link
We've been patient! Looked at all the ads multiple times for support to. Please drop the rest of the knowledge, Sir! "Still writing" on the overclocking page is nibblin' at my patience and intrigue hemisphere.Relic74 - Wednesday, August 29, 2018 - link
Yes of course there is, I have one of the new 32 core systems and I use it with SmartOS. A VM management OS that could allow up to 8 game developers to use a single 32 Core workstation without a single bit of performance lost. That is as long as each VM has control over their own GPU. 4 Cores(most games dont new more than that in fact, no game needs more that), 32GB to 64GB of RAM (depending on server config) and an Nvidia 1080ti or higher, per VM. That is more than enough and would save the company thousands, in fact, that is exactly what most game developers use. Servers with 8 to 12 GPU's, dual CPUs, 32 to 64 cores, 512GB of RAM, standard config.You should watch Linus Tech Tips 12 node gaming system off of a single computer, it's the future and is amazing.
eek2121 - Saturday, August 18, 2018 - link
You are downplaying the gaming market. It's a multi-billion dollar industry. Nothing niche about it.HStewart - Monday, August 13, 2018 - link
I agree with you - so this mainly concerning "It's over, Intel is finished"Normally I don't care much to discuss AMD related threads - but when people already bad mouth Intel, it all fair game in my opinion.
But what is important and why I agree is that it not even close. Because the like it or not, PC Game industry which primary reason for desktop now is a minimal part of industry now - computers are mostly going to mobile - and just go into local BestBuy and you see why it not even close.
Plus as in a famous WW II saying, "The Sleeper has been Awaken". One is got to be blind, if you think "Intel is finished" I think the real reason that 10nm is not coming out, is that Intel wants to shut down AMD for once and for always. I see this coming in two areas - in the CPU area and also with GPU - I believe the i870xG is precursor to it - with AMD GPU being replace with Artic Sound.
But AMD does have a good side to this. That it keep Intel's prices down and Intel improving products.
ishould - Monday, August 13, 2018 - link
"I think the real reason that 10nm is not coming out, is that Intel wants to shut down AMD for once and for always." This is actually not true, Intel is having *major* yield issues with 10nm, hence 14nm being a 4-year-node (possibly 5 years if it slips from the expected Holiday 2019), and is a contributing factor for the decline of Intel/rise of AMD.HStewart - Monday, August 13, 2018 - link
I not stating that Intel didn't have yield issues - but there is 2 things that should be taking in account - and of course Intel only really knows1. (Intel has stated this) That all 10nm are not equal - and then Intel's 10nm is closer to competition's 7nm - and this is likely the reason why it taking long.
2. Intel realizes the process issues - and if you think they are not aware of competition in market - not just AMD but also ARM then one is a fool
ishould - Monday, August 13, 2018 - link
I agree they were probably being too ambitious with their scaling (2.4x) for 10nm. Rumor is that they've had to sacrifice some scaling to get better yields. EUV cannot come soon enough!MonkeyPaw - Monday, August 13, 2018 - link
I highly highly doubt that Intel would postpone 10nm just to “shut down AMD.” Intel has shareholders to look out for, and Intel needs 10nm out the door yesterday. Their 10nm struggles are real, and it is costing them investor confidence. No way would they wait around to win a pissing match with AMD while their stock value goes down.