"It looks the same on the powerpoint slide, but they are very different". The place is Austin, where an AMD engineer is commenting on the slides describing the Zen and Skylake schematics. In Portland, the Intel representatives could not agree more: "the implementation matters and is completely different". "We have to educate our customers that they can not simply compare AMD's 32 core with our 28 cores".

This morning kicks off a very interesting time in the world of server-grade CPUs. Officially launching today is Intel's latest generation of Xeon processors, based on the "Skylake-SP" architecture. The heart of Intel's new Xeon Scalable Processor family, the "Purley" 100-series processors incorporate all of Intel's latest CPU and network fabric technology, not to mention a very large number of cores.

Meanwhile, a couple of weeks back AMD soft-launched their new EPYC 7000 series processors. Based on the company's Zen architecture and scaled up to server-grade I/O and core counts, EPYC represents an epic achievement for AMD, once again putting them into the running for competitive, high performance server CPUs after nearly half a decade gone. EPYC processors have begun shipping, and just in time for today's Xeon launch, we also have EPYC hardware in the lab to test.

Today's launch is a situation that neither company has been in for quite a while. Intel hasn't had serious competition in years, and AMD has't been able to compete. As a result, both companies are taking the other's actions very seriously.

In fact we could go on for much longer than our quip above in describing the rising tension at the headquarters of AMD and Intel. For the first time in 6 years (!), a credible alternative is available for the newly launched Xeon. Indeed, the new Xeon "Skylake-SP" is launching today, and the yardstick for it is not the previous Xeon (E5 version 4), but rather AMD's spanking new EPYC server CPU. Both CPUs are without a doubt very different: micro architecture, ISA extentions, memory subsystem, node topology... you name it. The end result is that once again we have the thrilling task of finding out how the processors compare and which applications their various trade-offs make sense.

The only similarity is that both server packages are huge. Above you see the two new Xeon packages –with and without an Omni-Path connector – both of which are as big as a keycard. And below you can see how one EPYC CPU fills the hand of AMD's CEO Dr. Lisa Su. 

Both are 64 bit x86 CPUs, but that is where the similarities end. For those of you who have been reading Ian's articles closely, this is no surprise. The consumer-focused Skylake-X is the little brother of the newly launched Xeon "Purley", both of which are cut from the same cloth that is the Skylake-SP family. In a nutshell, the Skylake-SP family introduces the following new features: 

  1. AVX-512 (Many different variants of the ISA extension are available)
  2. A 1 MB (instead of a 256 KB) L2-cache with a non-inclusive L3
  3. A mesh topology to connected the cores and L3-cache chunks together

Meanwhile AMD's latest EPYC Server CPU was launched a few weeks ago:

On the package are four silicon dies, each one containing the same 8-core silicon we saw in the AMD Ryzen processors. Each silicon die has two core complexes, each of four cores, and supports two memory channels, giving a total maximum of 32 cores and 8 memory channels on an EPYC processor. The dies are connected by AMD’s newest interconnect, the Infinity Fabric...

In the next pages, we will be discussing the impact of these architectural choices on server software. 

AMD's EPYC Server CPU
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  • PixyMisa - Thursday, July 13, 2017 - link

    Epyc has been out for three weeks. Reply
  • 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 improvement Reply
  • PixyMisa - 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. Reply
  • Shankar1962 - Sunday, July 16, 2017 - link

    Mind your language asshole
    Either 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
    Reply
  • PixyMisa - Tuesday, July 25, 2017 - link

    I'm sorry you're an idiot. Reply
  • 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. Reply
  • 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. Reply
  • 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.
    Reply
  • davide445 - Wednesday, July 12, 2017 - link

    Finally real competition in the HPC market. Waiting for the next top500 AMD powered supercomputer. Reply
  • 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
    Reply

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