Sizing Up Servers: Intel's Skylake-SP Xeon versus AMD's EPYC 7000 - The Server CPU Battle of the Decade?
by Johan De Gelas & Ian Cutress on July 11, 2017 12:15 PM EST- Posted in
- CPUs
- AMD
- Intel
- Xeon
- Enterprise
- Skylake
- Zen
- Naples
- Skylake-SP
- EPYC
Intel’s Turbo Modes
A last minute detail from Intel yesterday was information on the Turbo modes. As expected, not all of the processors actually run at their rated/base frequency: most will apply a series of turbo modes depending on how many cores are registered as ‘active’. Each core can have its frequency adjusted independently, allowing VMs to take advantage of different workload types and not be hamstrung by occupants on other VMs in the same socket. This becomes important when AVX, AVX2 and AVX-512 are being used at the same time.
Most of the turbo modes are a sliding scale, with the peak turbo used when only one or two cores are active, sliding down to a minimum frequency that may be the ‘base’ frequency or just above it. There’s a lot of information for the parts here, so we’ll break it down into stages.
First up, a look at the Platinum 8180 in the different modes:
It should be worth noting what the base frequency actually is, and some of the nuance in Intel’s wording here. The base frequency is the guaranteed frequency of the chip – Intel sells the chip with the base frequencies as the guarantee, such that when the chip is not idle and not in normal conditions (i.e. when not in thermal power states to reduce temperature) should operate at this frequency or above it. Intel also lists the per-core turbo frequencies as ‘Maximum Core Frequencies’ indicating that the processors could be running lower than listed, depending on power distribution and requirements in other areas of the chip (such as the uncore, or memory controller). It’s a vague set of terms but ultimately the frequency is determined on the fly and can be affected by many factors, but Intel guarantees a certain amount and provides guides as to what it expects the turbo frequencies to be.
As for the Platinum 8180, it keeps its top turbo modes while up to two cores are active, and then drops down. It does this again for another two cores, and a further two cores. From this point, under non-AVX load the CPU is pretty much the same frequency until >20 cores are loaded, but does not decrease that much in all. For AVX 2.0 and AVX-512, the downward slope of more cores means less frequency continues, with AVX-512 taking a bigger jump down at 13 cores loaded. The final turbo frequency for AVX-512 running on all cores is 2.3 GHz.
Comparing the two 28-core CPUs for which we have turbo information gives this graph. The numbers relate to the number of cores need to be loaded for that frequency.
Both processors are equal to each other for dual core loading, but the separation occurs when more cores are loaded. As we move through to AVX 2.0 and AVX-512, it is clear where the separations are in performance – to get the best for variable core loading, the more expensive processors are required.
Here’s the big table for all the processors on Non-AVX loading:
Despite the 2.0/2.1 GHz base on most of the Platinum series, all the CPUs will turbo up to 3.7-3.8 GHz on low core loading except for the lower power Platinum 8153. For users wanting to strike a good balance between the core count and frequency, the Gold 6154 is probably the place to be: 18 cores that will only ever run at 3.7 GHz with non-AVX loading (3.5-2.7 GHz on AVX-512 depending on core count), and will be $3543 as a list price at 205W. It is perhaps worth noting that this will likely top any of the Core i9 processors planned: at 18-cores and 205W for 3.7 GHz, the Core i9-7980XE which will have 18 cores but run 165W will likely be clocked lower (but also only ~$2000).
Moving onto AVX2.0 and AVX-512:
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Shankar1962 - Thursday, July 13, 2017 - link
So you think Intel won't release anything new again by then? Intel would be ready for cascadelake by then. None of the big players won't switch to AMD. Skylake alone is enough to beat epyc handsomely and cascadelake will just blow epyc. Its funny people are looking at lab results when real workloads are showing 1.5-1.7x speed improvementPixyMisa - Saturday, July 15, 2017 - link
This IS comparing AMD to Intel's newest CPUs, you idiot. Skylake loses to Epyc outright on many workloads, and is destroyed by Epyc on TCO.Shankar1962 - Sunday, July 16, 2017 - link
Mind your language assholeEither continue the debate or find another place for your shit and ur language
Real workloads don't happen in the labs you moron
Real workloads are specific to each company and Intel is ahead either way
If you have the guts come out with Q3 Q4 2017 and 2018 revenues from AMD
If you come back debating epyc won over skylake if AMD gets 5-10% share then i pity your common sense and your analysis
You are a bigger idiot because you spoiled a healthy thread where people were taking sides by presenting technical perspective
PixyMisa - Tuesday, July 25, 2017 - link
I'm sorry you're an idiot.Shankar1962 - Thursday, July 13, 2017 - link
Does not matter. We can debate this forever but Intel is just ahead and better optimized for real world workloads. Nvidia i agree is a potential threat and ahead in AI workloads which is the future but AMD is just an unnecessary hype. Since the fan boys are so excited with lab results (funny) lets look at Q3,Q4 results to see how many are ordering to test it for future deployment.martinpw - Wednesday, July 12, 2017 - link
I'm curious about the clock speed reduction with AVX-512. If code makes use of these instructions and gets a speedup, will all other code slow down due to lower overall clock speeds? In other words, how much AVX-512 do you have to use before things start clocking down? It feels like it might be a risk that AVX-512 may actually be counterproductive if not used heavily.msroadkill612 - Wednesday, July 12, 2017 - link
(sorry if a repost)Well yeah, but this is where it starts getting weird - 4-6 vega gpuS, hbm2 ram & huge raid nvme , all on the second socket of your 32 core, c/gpu compute ~Epyc server:
https://marketrealist.imgix.net/uploads/2017/07/A1...
from
http://marketrealist.com/2017/07/how-amd-plans-to-...
All these fabric linked processors, can interact independently of the system bus. Most data seems to get point to point in 2 hops, at about 40GBps bi-directional (~40 pcie3 lanes, which would need many hops), and can be combined to 160GBps - as i recall.
Suitably custom hot rodded for fabric rather than pcie3, the nvme quad arrays could reach 16MBps sequential imo on epycs/vegaS native nvme ports.
To the extent that gpuS are increasing their role in big servers, intel and nvidea simply have no answer to amd in the bulk of this market segment.
davide445 - Wednesday, July 12, 2017 - link
Finally real competition in the HPC market. Waiting for the next top500 AMD powered supercomputer.Shankar1962 - Wednesday, July 12, 2017 - link
Intel makes $60billion a year and its official that Skylake was shipping from Feb17 so i do not understand this excitement from AMD fan boys......if it is so good can we discuss the quarterly revenues between these companies? Why is AMD selling for very low prices when you claim superior performance over Intel? You can charge less but almost 40-50% cheap compared to Intel really?AMD exists because they are always inferior and can beat Intel only by selling for low prices and that too for what gaining 5-10% market which is just a matter of time before Intel releases more SKUs to grab it back
What about the software optimizations and extra BOM if someone switches to AMD?
What if AMD goes into hibernation like they did in last 5-6years?
Can you mention one innovation from AMD that changed the world?
Intel is a leader and all the technology we enjoy today happenned because of Intel technology.
Intel is a data center giant have head start have the resources money acquisitions like altera mobileeye movidus infineon nirvana etc and its just impossible that they will lose
Even if all the competent combines Intel will maintain atleast 80% share even 10years from now
Shankar1962 - Wednesday, July 12, 2017 - link
To add onNo one cares about these lab tests. Let's talk about the real world work loads.
Look at what Google AWS ATT etc has to say as they already switched to xeon sky lake
We should not really be debating if we have the clarity that we are talking about AMD getting just 5% -10% share by selling high end products they have for cheap prices....they fo not make too much money by doing that.....they have no other option as thats the only way they can dream of a 5-10% market share
For Analogy think Intel in semiconductor as Apple in selling smartphones
Intel has gross margins of ~63%
They have a solid product portfolio technologies and roadmap .....we can debate this forever but the revenues profits innovations and history between these companies can answer everything