"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. 

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  • msroadkill612 - Wednesday, July 12, 2017 - link

    It looks interesting. Do u have a point?

    Are you saying they have a place in this epyc debate? using cheaper ddr3 ram on epyc?
  • yuhong - Friday, July 14, 2017 - link

    "We were told from Intel that ‘only 0.5% of the market actually uses those quad ranked and LR DRAMs’, "
  • intelemployee2012 - Wednesday, July 12, 2017 - link

    what kind of a forum and website is this? we can't delete the account, cannot edit a comment for fixing typos, cannot edit username, cannot contact an admin if we need to report something. Will never use these websites from now on.
  • Ryan Smith - Wednesday, July 12, 2017 - link

    "what kind of a forum and website is this?"

    The basic kind. It's not meant to be a replacement for forums, but rather a way to comment on the article. Deleting/editing comments is specifically not supported to prevent people from pulling Reddit-style shenanigans. The idea is that you post once, and you post something meaningful.

    As for any other issues you may have, you are welcome to contact me directly.
  • Ranger1065 - Thursday, July 13, 2017 - link

    That's a relief :)
  • iwod - Wednesday, July 12, 2017 - link

    I cant believe what i just read. While I knew Zen was good for Desktop, i expected the battle to be in Intel's flavour on the Server since Intel has years to tune and work on those workload. But instead, we have a much CHEAPER AMD CPU that perform Better / Same or Slightly worst in several cases, using much LOWER Energy during workload, while using a not as advance 14nm node compared to Intel!

    And NO words on stability problems from running these test on AMD. This is like Athlon 64 all over again!
  • pSupaNova - Wednesday, July 12, 2017 - link

    Yes it is.

    But this time much worse for Intel with their manufacturing lead shrinking along with their workforce.
  • Shankar1962 - Wednesday, July 12, 2017 - link

    Competition has spoiled the naming convention Intels 14 === competetions 7 or 10
    Intel publicly challenged everyone to revisit the metrics and no one responded
    Can we discuss the yield density and scaling metrics? Intel used to maintain 2year lead now grew that to 3-4year lead
    Because its vertically integrated company it looks like Intel vs rest of the world and yet their revenue profits grow year over year
  • iwod - Thursday, July 13, 2017 - link

    Grew to 3 - 4 years? Intel is shipping 10nm early next year in some laptop segment, TSMC is shipping 7nm Apple SoC in 200M yearly unit quantity starting next September.

    If anything the gap from 2 - 3 years is now shrink to 1 to 1.5 year.
  • Shankar1962 - Thursday, July 13, 2017 - link

    Yeah 1-1.5 years if we cheat the metrics when comparison
    2-3years if we look at metrics accurately
    A process node shrink is compared by metrics like yield cost scaling density etc
    7nm 10nm etc is just a name

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